bluuebunny/crossref_metadata_2025 huggingface dataset:
Introduction to Power Boilers
Authors: Ortman Ed , Vattappilly Jay
Published: June 2023

Section I of the ASME Boiler and Pressure Vessel Code provides rules for the construction of power boilers. This chapter provides an overview of the requirements of Section I and explains how they are applied and enforced. The discussion begins with an outline of the history, philosophy, and scope of Section I, how the ASME Code works, and how it is organized. The chapter then addresses the distinction between boiler proper piping and boiler external piping, and describes how and where Section I is enforced. This is followed by a discussion on the fundamentals of Section I construction. The fundamentals include permitted materials, design, fabrication, welding and postweld heat treatment, nondestructive examination, hydrostatic testing, third-party inspection, and certification by stamping and the use of data reports. The chapter ends by highlighting some of the items which may be included in a future publication of Section I. A few of these include changes to the requirements of pressure testing of replacement parts; changes to the requirements for marking of plate material used for shells, furnace sheets, and heads; and inclusion of corrosion allowance application criteria.

History

Martin D. Bernstein was the originator of this chapter for the first edition. Lloyd W. Yoder updated the chapter for the second edition. John R. MacKay updated the chapter for both the third and fourth editions. Ed Ortman and Jay Vattappilly updated this chapter for the fifth edition. Ed Ortman updated this chapter for the current online edition.
ASME Section IV: Rules for the Construction of Heating Boilers
Authors: Smith Clayton T.
Published: June 2023

This chapter presents the rules of the ASME Boiler and Pressure Vessels Code, Section IV, constituting the minimum requirements for the safe design, construction, installation, and inspection of low-pressure steam boilers and hot-water Boilers (which are directly fired with oil, gas, electricity, or other solid or liquid fuels). It is divided into five parts and two sub-parts including several appendices. Part HG addresses the material requirements, design, pressure-relieving devices, tests, inspection, stamping, instruments, fittings and controls, and the installation of low-pressure steam-heating boilers, hot-water-heating boilers, hot-water-supply boilers, and the boilers’ appurtenances. Part HF, dealing with requirements for heating boilers constructed of wrought materials, has two sub-parts: HW and HB. The requirements of HW are applicable to heating boilers and their parts fabricated by welding. HB addresses the requirements for steam-heating boilers, hot-water-heating boilers, hot-water-supply boilers, and the boilers’ fabrication by brazing. The requirements of Part HC apply to steam-heating boilers, hot water-heating boilers, and hot-water-supply boilers and their parts, which are fabricated primarily of cast iron. The requirements of Part HA apply to hot water boilers constructed primarily of cast aluminum. Part HLW addresses the requirements for water heaters in commercial or industrial settings for supplying potable water at pressures not exceeding 160 psig (1100 kPa) and temperatures not exceeding 210°F (99°C). For each part, general requirements, material specifications, design parameters and calculations, fabrication requirements, and information on testing, inspection, and stamping are given. Appendices contained in this chapter include methods of checking safety valve and safety relief valve capacity; examples of methods of calculating a welded ring reinforced furnace; examples of methods of computation of openings in boiler shells; glossary; and two examples of manufacturer’s data report forms.
Section VII—Recommended Guidelines for the Care of Power Boilers
Authors: Mollitor Barrie , Lowry William L.
Published: June 2023

This chapter covers ASME Boiler and Pressure Vessel Code Section VII, which presents guidelines for safe, reliable operation as well as avoiding unsafe conditions in power boilers. The guidelines apply to power boilers that produce steam for external use at a pressure exceeding 15 psig from the application of heat, which come from the combustion of fuels, from various hot waste gases, or from the application of electrical energy. The bulk of this chapter is devoted to the discussion on Subsection 1 of Section VII, which contains information about industrial, gas- or oil-fired, watertube boilers. Subsection 1 introduces the fundamentals of watertube boilers, the principles of boiler operation, the associated auxiliaries, and appurtenances required by ASME Code Section I. It also introduces the necessary instrumentation, the examinations to be performed by boiler operators and staff, and the requirements for repairs, alterations, and maintenance. Subsection 2 presents an overview of the control of chemical conditions within steam boilers. It provides information relating to internal cleaning and laying-up of boilers, internal corrosion due to deposits within boiler tubes, and corrosion cracking. The discussion covers the types of water treatment problems within boilers, and how each problem may be recognized and corrected so as to prevent boiler failures. Subsection 3 deals with firetube, electric, and utility boilers and Subsection 4 includes all information pertaining to coal-fired and other solid-fuel-fired boilers. Articles in Subsection 4 describe the types of ash and their removal and contain short generic lists of maintenance checks for these boilers. Subsection 5 is a glossary of the terms that may be used when referring to a power boiler and its associated facilities. Section VII is a practical boiler book, a good review for experienced personnel and a good teaching aid for less-experienced personnel.

History

The original author of this chapter was Edmund W. K. Chang. The second and third editions were updated by Edmund W. K. Chang and Geoffrey M. Halley.

The fourth edition was updated by James T. Pillow. The fifth edition was completely revised by William L. Lowry. Barrie Mollitor updated this chapter for the current online edition.
Subsection NB, NC, ND-3600 Piping
Authors: Gray Mark A. , Cole Jack R.
Published: June 2023

This chapter provides a commentary on the criteria and basis for requirements of Subsections NB, NC, and ND for Piping. It presents information on the corresponding design processes and design specifications, with pertinent references, tables, and figures. The chapter addresses service limits and loading conditions classified as Levels A, B, C, and D. The Code rules assure that violation of the pressure boundary will not occur if the design specification satisfactorily addresses all issues necessary for Code compliance. This assurance is provided in the following ways: protection against catastrophic failure and protection against initiation and propagation of a crack or propagation of a Section III acceptable flaw through the pressure boundary. The chapter addresses how Section III provides this protection, any variations that exist or that have existed between the piping rules and the design-by-analysis rules, and what items the analyst should be concerned with in satisfying Code requirements. It helps alleviate the confusion regarding the proper application of ANSI B31.7 rules. As the requirements of NB-3600 are discussed, the important areas are compared to those of NB-3200. The chapter also shows that for primary stress protection, NB-3200 and NB-3600 are quite different, but in the secondary and peak stress areas, including fatigue, the basis for the rules is essentially the same although the analytical approach is quite different. It then covers rules for both Class 2 (NC-3600) and Class 3 (ND-3600) piping design. The chapter also explains the importance of a design specification. Finally, it discusses the need for a process of analysis with release of information that needs to be established to provide an orderly flow of information, to assure timely pipe fabrication and support delivery, and to issue stress reports at reasonable times.

History

Donald F. Landers was the original author who updated the chapter for the second and third editions. The fourth edition was revised by Jack R. Cole. The fifth edition was updated by Jack R. Cole and Mark A. Gray are. The current online edition was updated by Mark A. Gray and reviewed by George Z. Tokarski.
How Movement Habits Become Relevant in Novel Learning Situations
Authors: Barker Dean , Larsson Hakan , Nyberg Gunn
Published: June 2023

Purpose: To (a) present a theoretical framework that describes how learners’ movement habits become relevant in the development of movement capability and (b) present data that illustrate how this process occurs in practice. Method: An investigation with preservice physical education teachers was conducted in two phases. The first phase involved examining participants’ movement habits, and the second phase involved examining the participants’ development of novel capabilities in the context of unicycling. Results: Empirical materials from two participants are presented as case studies. The cases demonstrate how different sets of movement habits interact with novel tasks, making the demand for creative action more or less likely. The cases also demonstrate how subjective and physical elements are interwoven. Finally, the cases provide insights into potentially productive habits for movement learning. Discussion/Conclusion: The paper is concluded with pedagogical implications, including a consideration of how crises might be managed in educational contexts.
‘Space to talk’: a Portuguese focus group study of parents’ experiences, needs and preferences in parenting support during prenatal and well-child care
Authors: Fareleira Filipa , Xavier Maria Raul , Tavares de Lima Filipa , Sampaio Reis Helena , Velte Julia , Martins Carlos
Published: June 2023

Objective

To explore the experiences, needs and preferences of a group of parents regarding the parenting support received during prenatal and well-child care in the Portuguese National Health Service.

Design and setting

We undertook descriptive-interpretive qualitative research running multiple focus groups in Porto, Northern Portugal.

Participants, data collection and analysis

Purposive sampling was used between April and November 2018. Focus groups were conducted with 11 parents of a 0–3 years old with well-child visits done in primary care units. Thematic analysis was performed in a broadly inductive coding strategy and findings are reported in accordance with Consolidated Criteria for Reporting Qualitative Research guidelines.

Results

Three main themes were identified to describe parents’ experience when participating in their children’s healthcare: (1) logistics/delivery matter, including accessibility, organisation and provision of healthcare activities, unit setting and available equipment; (2) prenatal and well-child care: a relational place to communicate, with parents valuing a tripartite space for the baby, the family and the parent himself, where an available and caring health provider plays a major role and (3) parenting is challenging and looks for support, based on key points for providers to watch for and ask about, carefully explained and consensual among health providers.

Conclusion

This study provides insight into parents’ needs and healthcare practices that affect the parenting experience. To meet parents’ preferences, sensitive health providers should guarantee a relational place to communicate and person-centredness, accounting for the whole family system to support healthy parenting collaboratively. Future studies are warranted to further strengthen the knowledge in the field of a population-based approach for parenting support.
Development and validation of a rurality index for healthcare research in Japan: a modified Delphi study
Authors: Kaneko Makoto , Ikeda Takaaki , Inoue Machiko , Sugiyama Kemmyo , Saito Manabu , Ohta Ryuichi , Cooray Upul , Vingilis Evelyn , Freeman Thomas R , Mathews Maria
Published: June 2023

Objectives

Rural–urban healthcare disparities exist globally. Various countries have used a rurality index for evaluating the disparities. Although Japan has many remote islands and rural areas, no rurality index exists. This study aimed to develop and validate a Rurality Index for Japan (RIJ) for healthcare research.

Design

We employed a modified Delphi method to determine the factors of the RIJ and assessed the validity. The study developed an Expert Panel including healthcare professionals and a patient who had expertise in rural healthcare.

Setting

The panel members were recruited from across Japan including remote islands, mountain areas and heavy snow areas. The panel recruited survey participants whom the panel considered to have expertise.

Participants

The initial survey recruited 100 people, including rural healthcare providers, local government staff and residents.

Primary outcome measures

Factors to include in the RIJ were identified by the Expert Panel and survey participants. We also conducted an exploratory factor analysis on the selected factors to determine the factor structure. Convergent validity was examined by calculating the correlation between the index for physician distribution and the RIJ. Criterion-related validity was assessed by calculating the correlation with average life expectancy.

Results

The response rate of the final survey round was 84.8%. From the Delphi surveys, four factors were selected for the RIJ: population density, direct distance to the nearest hospital, remote islands and whether weather influences access to the nearest hospital. We employed the factor loadings as the weight of each factor. The average RIJ of every zip code was 50.5. The correlation coefficient with the index for physician distribution was −0.45 (p<0.001), and the correlation coefficients with the life expectancies of men and women were −0.35 (p<0.001) and −0.12 (p<0.001), respectively.

Conclusion

This study developed the RIJ using a modified Delphi method. The index showed good validity.
Cognitive and other neuropsychiatric symptoms in COVID-19: analysis of person-generated longitudinal health data from a community-based registry
Authors: Largent Joan , Xie Yiqiong , Knuth Kendall B , Toovey Stephen , Reynolds Matthew W , Brinkley Emma , Mack Christina D , Dreyer Nancy A
Published: June 2023

Objective

To describe cognitive symptoms in people not hospitalised at study enrolment for SARS-CoV-2 infection and associated demographics, medical history, other neuropsychiatric symptoms and SARS-CoV-2 vaccination.

Design

Longitudinal observational study.

Setting

Direct-to-participant registry with community-based recruitment via email and social media including Google, Facebook and Reddit, targeting adult US residents. Demographics, medical history, COVID-19-like symptoms, tests and vaccinations were collected through enrolment and follow-up surveys.

Participants

Participants who reported positive COVID-19 test results between 15 December 2020 and 13 December 2021. Those with cognitive symptoms were compared with those not reporting such symptoms.

Main outcome measure

Self-reported cognitive symptoms (defined as ‘feeling disoriented or having trouble thinking’ from listed options or related written-in symptoms)

Results

Of 3908 participants with a positive COVID-19 test result, 1014 (25.9%) reported cognitive symptoms at any time point during enrolment or follow-up, with approximately half reporting moderate/severe symptoms. Cognitive symptoms were associated with other neuropsychiatric symptoms, including dysgeusia, anosmia, trouble waking up, insomnia, headache, anxiety and depression. In multivariate analyses, female sex (OR, 95% CI): 1.7 (1.3 to 2.2), age (40–49 years (OR: 1.5 (1.2–1.9) compared with 18–29 years), history of autoimmune disease (OR: 1.5 (1.2–2.1)), lung disease (OR: 1.7 (1.3–2.2)) and depression (OR: 1.4 (1.1–1.7)) were associated with cognitive symptoms. Conversely, black race (OR: 0.6 (0.5–0.9)) and COVID-19 vaccination before infection (OR: 0.6 (0.4–0.7)) were associated with reduced occurrence of cognitive symptoms.

Conclusions

In this study, cognitive symptoms among COVID-19-positive participants were associated with female gender, age, autoimmune disorders, lung disease and depression. Vaccination and black race were associated with lower occurrence of cognitive symptoms. A constellation of neuropsychiatric and psychological symptoms occurred with cognitive symptoms. Our findings suggest COVID-19’s full health and economic burden may be underestimated.

Trial registration number

NCT04368065.
Temporal structures that determine consistency and quality of care: a case study in hyperacute stroke services
Authors: Black Georgia B , Ramsay Angus I G , Simister Robert , Baim-Lance Abigail , Eng Jeannie , Melnychuk Mariya , Fulop Naomi J
Published: June 2023

Background

Temporal structuring is determined by practices and social norms and affects the quality and timing of care
. In this case study of hyperacute stroke wards which provide initial stroke investigation, treatment and care, we explored temporal structuring patterns to explain how these may affect quality of care.

Methods

This paper presents a thematic analysis of qualitative interviews with hyperacute stroke staff (n=76), non-participant observations (n=41, ~102 hours) and documentary analysis of the relevant service standards guidance. We used an inductive coding process to generate thematic findings around the concept of temporal structuring, with graphically illustrated examples.

Results

Five temporal structures influence what-happens-when: (1) clinical priorities and quality assurance metrics motivate rapid activity for the initial life-prolonging assessments and interventions; (2) static features of ward organisation such as rotas and ward rounds impact consistency of care, determining timing and quality of care for patients; (3) some services experimented with staff rotas to try to meet peaks in demand, sometimes unsuccessfully; (4) implicit social norms or heuristics about perceived necessity affected staff motivation to make changes or improvements to consistency of care, particularly around weekend work; and (5) after-effects such as bottlenecks or backlogs affect quality of care, which are hard to measure effectively to drive service improvement.

Conclusions

Patients need temporally consistent high quality of care. Temporal consistency stems from the design of services, including staffing, targets and patient pathway design as well as cultural attitudes to working patterns. Improvements to consistency of care will be limited without changes to structures such as rotas and ward rounds, but also social norms around weekend work for certain professional groups.
Current advances in microbiome sciences within the US Department of Defense: part 2 � enabling technologies and environmental microbiomes
Authors: Colston Sophie M , Barbato R A , Goodson M S , Karl J P , Kokoska R J , Leary D D , Racicot K , Varaljay V , Soares J W
Published: June 2023

Microbiomes involve complex microbial communities wherein the micro-organisms interact with one another as well as their associated hosts or environmental niches. Much of the characterisation of these communities and the associations have been achieved through �omics� technologies, such as metagenomics, metaproteomics and metametabolomics, and model systems. Recent research in host-associated microbiomes has been aimed at understanding the role microbes may play in host fitness or conversely how host activities/conditions may perturb the microbial community, which can further affect host health. These studies have led to the investigation of detection, intervention or modulation methods, which may serve to provide benefits to the host and advance our understanding of microbiome associations. With the clear implications on human health and disease, the US Department of Defense (DoD) has made microbiome research a priority, with the founding of the Tri-Service Microbiome Consortium (TSMC) to enhance collaboration, coordination,and communication of microbiome research among DoD organisations and partners in academia and industry. DoD microbiome research focuses mainly on the following themes: (1) human health and performance, (2) environmental microbiomes and (3) enabling technologies. This review provides an update of current DoD microbiome research efforts centred on enabling technologies and environmental microbiomes and highlights innovative research being done in academia and industry that can be leveraged by the DoD. These topics were also communicated and further discussed in the Fifth Annual TSMC Symposium. This paper forms part of the special issue of
BMJ Military Health
dedicated to personalised digital technology for mental health in the Armed Forces.
Equivalence, Unambiguity, and Sequentiality of Finitely Ambiguous Max-Plus Tree Automata
Authors: Paul Erik
Published: June 2023

We show that the equivalence, unambiguity, and sequentiality problems are decidable for finitely ambiguous max-plus tree automata. A max-plus tree automaton is a weighted tree automaton over the max-plus semiring. A max-plus tree automaton is called finitely ambiguous if the number of accepting runs on every tree is bounded by a global constant and it is called unambiguous if there exists at most one accepting run on every tree. For the equivalence problem, we show that for two finitely ambiguous max-plus tree automata, it is decidable whether both assign the same weight to every tree. For the unambiguity and sequentiality problems, we show that for every finitely ambiguous max-plus tree automaton, both the existence of an equivalent unambiguous automaton and the existence of an equivalent deterministic automaton are decidable.
A note about the maximum local time of a random walk on the square lattice
Authors: do Amaral Charles S.
Published: June 2023

This paper conducts a numerical analysis of the behavior of the average value of the Maximum Local Time, [Formula: see text], in the Simple Random Walk on the square lattice. It has been established in the literature that the sequence [Formula: see text] converges to [Formula: see text]. The author found numerical evidence that the average value of [Formula: see text] ([Formula: see text]) increases until a certain value of [Formula: see text], denoted as [Formula: see text], after which it decreases and approaches [Formula: see text]. Furthermore, estimates are presented for [Formula: see text] and [Formula: see text].
Logarithmic inflation?
Authors: Cristóbal Jose María Fernández
Published: June 2023

We consider a scalar–tensor action model, both simple and peculiar at the same time, with a boundary term added that it is form-invariant both under the conformal transformation of the metric as well as under the reparametrization of the scalar field. Under this assumption, the boundary term proposed matches (except factors) with the Gibbons–Hawking–York term proposed in such a way it cancels the term(s) involving [Formula: see text]. A matter term is added to the action also. In the Jordan frame, the pure gravitational action becomes the Einstein–Hilbert action with a cosmological constant when the scalar field takes the constant value of their vev, [Formula: see text], which is no otherwise but the only stable minimum of the classical potential chosen which is logarithmic type. This potential presents a large plateau in which it is almost fully flat and the decay of the field from its initial value (assumed to be close to [Formula: see text]) to vacuum draws a Low Field (or New Inflation) scenario. The model fits very well with the current paradigm of the universe and, under some assumptions, gives a good account of the value of the Higgs mass, the current value of the cosmological constant, e-folding, the Hubble parameter, the spectral index of scalar perturbations, etc. The model is not studied in Einstein’s frame. In this, only the expressions of the field and the potential, for a simple case, are achieved. As a result, we get that the nature of the decay of the initial value to its ground state for the scalar field, in this frame, should be by quantum tunneling and not by slow rolling.
Scattering of evanescent particles
Authors: Oeckl Robert
Published: June 2023

Massive Klein–Gordon theory is quantized on the timelike hypercylinder in Minkowski space. Crucially, not only the propagating, but also the evanescent sector of phase space is included, laying in this way foundations for a quantum scattering theory of fields at finite distance. To achieve this, the novel [Formula: see text]-Kähler quantization scheme is employed in the framework of general boundary quantum field theory. A potential quantization ambiguity is fixed by stringent requirements, leading to a unitary radial evolution. Formulas for building scattering amplitudes and correlation functions are exhibited. A novel LSZ formula is derived, applicable to scattering at finite distance.
Magnetohydrodynamic conjugate heat transfer analysis on a viscous fluid past a vertical permeable plate
Authors: Bhargavi N. , Poornima T. , Souayeh Basma
Published: June 2023

The influence of conjugate heat transfer based on radiation and magnetohydrodynamic utilization is an attractive research area, with progressive features; it has many applications in thermal engineering, heat exchangers, cooling phenomenon, magnetic cell separation, energy production, hyperthermia, etc. Following the motivating significances of the current research topic, this paper explores the influences of an electrically conducting and radiating fluid with internal friction, heat generation and thermal radiation embedded in a porous medium past a flat permeable plate. The boundary layer equations are dimensionally transformed and solved numerically using implicit finite difference technique called the Keller-box method. The effect of various fluid obeying parameters such as magnetic field, viscous dissipation and heat generation on the flow factors such as velocity and temperature are graphed and discussed in this paper. Growing heat source, energy inside the fluid boosts, thereby increasing the energy of the flow. Increase in generation of energy reduces the viscosity of the flow reduces thereby increasing the velocity of the flow particles.
Effect of particle shape on the heat transfer of magnetohydrodynamic nanofluid with dissipative energy and inertial drag
Authors: Pattnaik P. K. , Behera S. , Mishra S. R. , Dash A. K.
Published: June 2023

This investigation focuses on the nanoparticle shape effect on the flow of conducting non-Newtonian Maxwell nanoliquid through an absorptive expanding surface. Insertion of inertial drag due to the Darcy–Forchheimer model and the dissipative heat in the flow phenomena supplements the work. The thermal properties of the fluid show its important role because of the use of various thermophysical models such as the Gharesim model of viscosity and the Mintsa model of thermal conductivity. The proposed mathematical model is designed by the implementation of suitable similarity transformations and then a numerical scheme is adopted to solve the transformed phenomena. In particular, shooting-based traditional Runge–Kutta (RK) fourth order is implemented for the solution. The behavior of the parameters that are participating in the flow phenomena is deployed via graphs and the computation of the engineering coefficients is displayed in tables. The impression of innumerable governing flow constraints is interpreted with the validation of these investigations with the earlier investigation. However, the major outcomes are; the particle concentration contributes its significant characteristics in enhancing the fluid velocity as well as temperature for the increasing shape. The dissipative heat formulated by the Eckert number also augments the fluid temperature in association with the thermal radiation whereas the unsteadiness parameter retards it significantly.
Effects of applied external fields on the nonlinear optical second harmonic generation in a GaAs/Ga0.7Al0.3As quantum dots
Authors: Zhang Xiaosen
Published: June 2023

This work has studied some nonlinear optical properties of Al0.3Ga0.7As/GaAs quantum dot system with tangent-square potential (TSP), with special emphasis on the role of second harmonic generation (SHG) coefficient under hydrostatic pressure and temperature. Due to the strain of external application conditions, the changes of the energy level and wave function of the neutron band in the system structure provide valuable insights into the optical properties of the quantum dot structure. In this paper, we report the effects of structural parameters, temperature and hydrostatic pressure on the SHG coefficient. According to the results obtained in the work, it can be reported that the nonlinear optical properties of the quantum dot system can be improved by adjusting the hydrostatic pressure and temperature. At the same time, the interaction of various parameters has produced some interesting observations, which are relevant in relevant research fields.
Phase sensitivity and entanglement of superposition coherent states in Mach–Zehnder interferometer
Authors: Ren Gang , Chen Feng
Published: June 2023

In this paper, we mainly focus on analyzing the fidelity, parity measurement, phase sensitivity and entanglement properties of the output states corresponding to three quantum superposition coherent states, i.e. even coherent state (ECS), Yurke-Stoler state (YSS) and odd coherent state (OCS). Our results show that the OCS characterizes super-resolution in the phase measurement via parity measurement at the output ports of a Mach–Zehnder interferometer. In addition, we find that the optimal phase sensitivity may approach the Heisenberg limit which is independent of the superposition coefficient of the coherent states. An interesting finding is that the macroscopically entangled coherent states can be experimentally prepared by adjusting the parameters of the nonlinear phase shifter of the MZI.
Semigroups locally embeddable into the class of finite semigroups
Authors: Kudryavtsev D.
Published: June 2023

In this paper the concept of local embeddability into finite structures (being LEF) is examined for the class of semigroups. The established results include the connections to the previously studied class of LEF groups, residual finiteness, linear semigroups and the preservation of being LEF under certain semigroup constructions, such as adjoining zero or identity and taking direct, semidirect and wreath products.
BIFURCATION ANALYSIS OF AN ALLELOPATHIC PHYTOPLANKTON MODEL
Authors: CHEN SHANGMING , CHEN FENGDE , LI ZHONG , CHEN LIJUAN
Published: June 2023

This paper analyzes an allelopathic phytoplankton competition model, which was proposed by Bandyopadhyay [Dynamical analysis of a allelopathic phytoplankton model, J Biol Syst 14(02):205–217, 2006]. Our study refines the previous results and finds at most three positive equilibria for the system. The existence conditions of all positive equilibria and the corresponding stability cases are given in the paper. Interesting dynamical phenomena such as bistability, saddle-node bifurcation, and cusp bifurcation are found. It is shown that the rate of toxin releases heavily influences the positive equilibria of the system under certain conditions. Numerical simulations verify the feasibility of the theoretical results.
DYNAMICS OF A PREY–PREDATOR MODEL INCORPORATING GESTATION TIME DELAY AND FEAR EFFECT
Authors: LIU JUAN , UPADHYAY RANJIT KUMAR , AGRAWAL RASHMI , ZEB ANWAR , SAEED TAREQ
Published: June 2023

The anti-predator element because of fear from predator population in prey–predator models has an excellent significance and it is able to lessen the duplicate of prey population to a positive degree. In this paper, a delayed prey–predator model including fear effect and predator-taxis sensitivity is studied. Local stability and occurrence of Hopf bifurcation are analyzed by fixing the time delay as the bifurcating parameter. Then, a series of sufficient criteria for global stability is established by designing a suitable Lyapunov function. Furthermore, direction and stability of the Hopf bifurcation are studied. Lastly, numerical simulation outcomes are performed to confirm our theoretical findings.
A wavelet network-based speech enhancement system using noisy-as-clean strategy
Authors: Hajiaghababa Fatemeh , Abutalebi Hamid Reza
Published: June 2023

In recent years, the field of speech enhancement has greatly benefited from the rapid development of neural networks. However, the requirement for large amounts of noisy and clean speech pairs for training limits the widespread use of these models. Wavelet network-based speech enhancement typically relies on clean speech signals as a training target. This paper presents a new method that combines a neural network with the wavelet theory for speech enhancement without the need for clean speech signals as targets in training mode. Five wide evaluation criteria, namely short-time objective intelligibility (STOI), signal-to-noise ratio (SNR), segmental signal-to-noise ratio (SNRseg), weighted spectral slope (WSS) and logarithmic spectral distance (LSD), have been used to confirm the effectiveness of the proposed method. The results show that the proposed method performs similar to a wavelet neural network (WNN) trained with clean signals, or even superior to those obtained from the clean target-based strategies.
PDM Klein–Gordon particles in Som–Raychaudhuri cosmic string spacetime with space-like dislocation and a magnetic field: Spacetime associated degeneracies, vorticity-energy, and charge-energy correlations
Authors: Mustafa Omar
Published: June 2023

We explicitly study and report the effects of the gravitational fields on the spectroscopic structure of Klein–Gordon (KG) particles in Som–Raychaudhuri cosmic string spacetime with space-like dislocation and a magnetic field. We extend this study to include the effects of the gravitational fields on some position-dependent mass (PDM) KG-particles. As effects of the gravitational fields, we report new spacetime associated degeneracies, vorticity-energy correlations and charge-energy correlations. Such degeneracies and correlations are observed in the spectroscopic structure of both constant mass KG-particles and PDM KG-particles at hand.
Cd Form and Transition Study in Aquatic Environment by Gold Nanorods Attached with Sulfhydryl
Authors: Liu Shuyu , Tang Lei , Wu Zitong
Published: June 2023

Many biomolecular photothermal therapies in heavy metals detection are expensive and complicated. In this paper, compared to expensive and complex biomolecular photothermal therapy, a new type of coated nanomaterial was used to research Cd in water. We explored the assembly of glutathione-growth gold nanorods through the attachment of sulfhydryl groups on glutathione to the surface of gold nanorods, and studied the optimal incubation conditions for the preparation of Cd by reaction time and temperature. This study expounded the principle using the incubated gold nanorods, and quantitatively determined the content of Cd based on the ([Formula: see text] between two plasmon resonance absorption peaks of the gold nanorods. The linear range of the detection of isoniazid was 0.5–5.0[Formula: see text][Formula: see text]M, and the detection limit was 0.35[Formula: see text][Formula: see text]M. The recovery rates were 88.2–107.1%, and the results were satisfactory. This gold nanorods quantitative method was sensitive and feasible in Cd research in water environment application.
The Electrochromism and Photoelectrochemical Performance of WO3/Cu Composite Film Electrodes
Authors: Yang Jikai , Liu Haorui , Zhang Yufei
Published: June 2023

WO3/Cu composite film electrodes were synthesized by hydrothermal combined electrodeposition method. Characterization of samples was conducted by SEM, XRD and XPS, which showed WO3/Cu composite films had been synthesized. The diffusion coefficient, reversibility, response time, coloration efficiency and transmission rate of the samples were obtained by electrochemical and spectral measurements. The photocurrent and photoelectric catalysis degradation efficiency of the samples were obtained by photocurrent and photoelectric catalysis measurements. The WO3/Cu composite films improve electrochromic performance, photocurrent and photoelectric catalytic activity compared with pure WO3 nanoblocks, and the WO3/Cu composite film obtained by depositing Cu nanoparticles at 50 s shows the highest electrochromic performance, photocurrent and photoelectric catalytic activity. Meanwhile, the direct photocatalytic and electric catalytic activity of the composite film are also discussed. The combined effects of the lower band gap and the Schottky junction lead to significant enhancement in the electrochromic and photoelectrochemical properties of the WO3/Cu composite film.
Facial synthesis of core-shell nickel@carbon nanocomposite for high-efficient electrochemical detection of paracetamol
Authors: Zhao Zi-An , Xie Xuan , Liu Bo-Tao , Wu Hai-Ying , Zheng Yuan-Zhou , Tan Wei , Luo Yu-Hui , Zhang Dong-En
Published: June 2023

Nickel nanoparticles (Ni NPs) are attracting more and more attention in the field of electrochemistry due to their high conductivity and good catalytic properties. However, Ni NPs are susceptible to corrosion or agglomeration, leading to low stability. In this work, nickel@carbon nanomaterials (Ni@CNS) were prepared by pyrolysis nickel-based metal-organic framework (Ni-MOF) template, and characterized by powder X-ray diffraction (PXRD), transmission electron microscopy, scanning electron microscopy, Brunauer–Emmett–Teller method, and X-ray photoelectron spectroscopy (XPS). The prepared Ni@CNS composite reveals uniform core-shell structure, where the thin carbon shell not only protects the Ni NPs from being corroded, but also accelerates the migration of electrons, so as to promote its sensing performance. Ni@CNS composite presented as a black powder with mesoporous structure. The average size of Ni NPs was about 15.01 nm with a standard deviation of 3.21 nm. The specific surface area of Ni@CNS was as high as 116.12 m2 g[Formula: see text], which is beneficial to increase the effective surface area of the modified electrode. These structural advantages enhance its electrochemical performance toward paracetamol (PA) sensing. The Ni@CNS modified electrode has high sensitivity for quantitative detection of PA. The linear ranges were determined to be 0.570 [Formula: see text]M and 70432 [Formula: see text]M with a low detection limit of 0.028 [Formula: see text]M ([Formula: see text]/[Formula: see text] = 3). In addition, due to its excellent electrochemical performances, the constructed electrode was used to detect PA in real water samples. This work expands the application of Ni- and C-based composites in electrochemistry sensing.
SiOx/CNTs/Sn composite as high-performance anode material for lithium-ion batteries
Authors: Shi Anjun , Song Yu , Wu Ling , Cai Liangqiang , Gao Tian , Zhou Yu , Dou Aichun , Su Mingru
Published: June 2023

Despite its high theoretical specific capacity, direct application of SiO[Formula: see text] is challenging particularly in terms of alleviating volume effect and improving electronic conductivity to enhance the battery performance. SiO[Formula: see text]/CNTs/Sn composite with high cyclability and rate performance was proposed by a modified Stöber liquid phase method, CNTs and metallic tin were employed during the subsequent mechanical ball milling process to investigate their effects on the resulting physicochemical property and electrochemical performance. The structure of /CNTs/Sn composite was designed, and the multi-structure not only alleviates the volume effect of SiO[Formula: see text] to a certain extent but also provides additional diffusion pathways for lithium ions, electrons, and flexible substrate. From electrochemical characterization, the half-cell battery integrating SiO[Formula: see text]/CNTs/Sn anode exhibits a capacity of 880.83 mAh g[Formula: see text] with 6.3% capacity fading after 100 cycles at 0.1 A g[Formula: see text] and excellent rate performance. The simple and ingenious synthesis method could provide new development and application ideas for SiO[Formula: see text]-based anode materials.
Triangular Topology Sequence-Based Multi-Target Association for Aerial-Ground Unmanned Systems
Authors: Li Xudong , Wu Lizhen , Niu Yifeng , Zhou Huijie , Niu Jiaxin
Published: June 2023

The heterogeneous nature of aerial-ground unmanned systems has a considerable advantage in terms of full-area awareness. However, it also presents a great challenge in the multi-target association domain. The almost orthogonal observation view results in large parallax of the aerial-ground sensors large, rendering the trajectory association and visual feature association methods inapplicable. To address this problem, this paper proposes a multi-objective association method based on triangular topology from the relative position relationship of targets. First, the algorithm extracts the distance and azimuth of the target relative to the Unmanned Ground Vehicle based on its position in the sensor and constructs a triangular topology. Then, a bicircle matching model satisfying the triangular topological sequence association constraints is proposed to transform the constrained structure matching problem into an unconstrained one. Finally, an association algorithm based on the similarity association matrix is proposed to complete the association of topologies immediately by obtaining the “optimal path” in the matrix. Simulation experiments show that the correlation accuracy is above 80% when the interference target is less than 20%, and above 90% when the observation error is less than 2.0[Formula: see text]m. The overall performance of this method outperforms similar algorithms in comparative tests.
Economic Growth, Governance and CO2 Emissions in West Africa
Authors: IFELUNINI Innocent , EKPO Ugochinyere , AGBUTUN S. Adzugbele , ARAZU O. Winnie , UGWU C. Samuel , OSADEBE Nnabuike , ASOGWA O. Fredrick
Published: June 2023

Despite being the regions with the least levels of carbon emissions in the world, African countries are facing unique challenges on climate change, increased carbon emission levels and the need for environmental governance improvement. This study, therefore, examined the implications of economic growth and governance on CO2 emissions in West Africa. Specifically, the study investigated the role of governance in moderating the effect of economic growth on CO2 emissions in West Africa. The study utilized data for 16 West African countries from 2000 to 2020 in an unbalanced panel data framework. Empirical analyses were conducted using the Instrumental Variable Fixed Effects estimator with Driscoll and Kraay Standard Errors, as well as the Instrumental Variable Quantile Regression in order to account for serial correlation, endogeneity and conditional heteroskedasticity. The following conclusions were drawn from the results. First, economic growth significantly increases CO2 emissions in the region with the Environmental Kuznet Curve hypothesis present. Second, the quantile regression estimates reveal that the effect of economic growth on CO2 emissions is higher in countries where the initial level of carbon emissions is considerably high. Third, the results further show that in the presence of improved governance quality, economic growth does not significantly influence CO2 emissions in the region. Fourth, political stability and regulatory quality were the only indicators of governance that significantly impacted environmental pollution in the region. Finally, we found that other factors such as trade, urbanization, and renewable energy also significantly influenced CO2 emissions in the region. The study concludes by highlighting the importance of governance in moderating the effect of economic growth on CO2 emissions, as well as the importance of heterogeneous analysis for understanding the dynamism in economic relationships.
Engineering Rehabilitation: Blending Two Tool-supported Approaches to Close the Loop from Tasks-based Rehabilitation to Exercises and Back Again
Authors: Axel Carayon , Garrido Juan E. , Martinie Célia , Palanque Philippe , Barboni Eric , Lozano María Dolores , Penichet Víctor M. R.
Published: June 2023

Post-stroke or post-brain injuries rehabilitation is a long-term process defined by therapists and tuned to the specific damages and their consequences for each patient. This process requires the definition of well-defined multiple exercises to be performed multiple times by each patient over a long period of time. One of the key findings in the rehabilitation domain is that exercises should be tasks and goals oriented to increase functional independence, enhance development and prevent disability [24]. Patients performing the exercises must be carefully monitored to identify progress, possible regression and prevent damages due to the inadequate performance of the exercises. The SIVIRE tool [20] provides interactive graphical feedback to patients about the performance of their exercises and deviations from nominal, planed practice but fails at providing high-level descriptions of exercises and at connecting them to high-level rehabilitation goals (e.g. gain autonomy in cleaning a room). The HAMSTERS-XLE tool [16] provides a tuneable editor and a simulator to describe goals and task models including low-level tasks covering perception of the various senses, cognition and motoric actions. This paper presents the integration of these two tools and the benefits it brings both to the patients and to the therapists. The resulting tool and its engineering are presented in detail highlighting some generic integration mechanisms. On a case study, we show how exercises can be defined in HAMSTERS-XLE, transferred to SIVRE for fine tuning, monitored by SIVRE during the multiple practices of the patient and transferred back again to HAMSTERS-XLE to monitor progress, identify issues with the exercises and provide therapists with goal and task-based data about patients' evolutions
Low-cost and Non-visual Labels Using Magnetic Printing
Authors: Zhao Guanhua , Yan Yueli , Yang Zhice
Published: June 2023

This paper presents MagCode, a new type of barcode. MagCode label is printed with magnetic ink through ordinary printers and stores data in the magnetic field. By swiping a magnetometer over it, the stored data can be extracted. Thus, unlike ordinary barcodes, MagCode does not rely on visual channels to decode, implying untapped interaction opportunities when decoding ordinary visual code is not preferred or not possible. Its application cases include an unobstructed and low-cost input interface for wearables, whose visual sensing capabilities are usually limited. Further, MagCode's patterns can be designed to be visually-undecodable and our evaluation shows that accessing its magnetic signal requires very close approximation. These properties allow for using MagCode labels to convey covert and sensitive information, such as Easter eggs in games and payment credentials in daily life.
XRSpotlight: Example-based Programming of XR Interactions using a Rule-based Approach
Authors: Frau Vittoria , Spano Lucio Davide , Artizzu Valentino , Nebeling Michael
Published: June 2023

Research on enabling novice AR/VR developers has emphasized the need to lower the technical barriers to entry. This is often achieved by providing new authoring tools that provide simpler means to implement XR interactions through abstraction. However, novices are then bound by the ceiling of each tool and may not form the correct mental model of how interactions are implemented. We present XRSpotlight, a system that supports novices by curating a list of the XR interactions defined in a Unity scene and presenting them as rules in natural language. Our approach is based on a model abstraction that unifies existing XR toolkit implementations. Using our model, XRSpotlight can find incomplete specifications of interactions, suggest similar interactions, and copy-paste interactions from examples using different toolkits. We assess the validity of our model with professional VR developers and demonstrate that XRSpotlight helps novices understand how XR interactions are implemented in examples and apply this knowledge in their projects.