bluuebunny/crossref_metadata_2025 huggingface dataset:
Gill morphology and morphometry of the facultative air‐breathing armoured catfish,Corydoras paleatus, in relation on aquatic respiration
Authors: Plaul Silvia E. , Díaz Alcira O. , Barbeito Claudio G.
Published: June 2021

The Neotropical armoured catfishCorydoras paleatusis a facultative air‐breathing teleost commonly exported as ornamental fish. In this species, air breathing enables it to survive and inhabit freshwater environments with low oxygen levels. Therefore, it is important to analyse the gills from a morphological aspect and its dimensions in relation to body mass with reference to aquatic respiration. For that, the gills were analysed using a stereoscopic microscope for morphometric studies, and structural and ultrastructural studies were carried out to compare the four branchial arches. Furthermore, two immunohistochemical techniques were used to locate and identify the presence of a Na+/K+pump. The characterization of the potential for cell proliferation of this organ was assessed using an anti‐PCNA antibody. The results show that gills ofC. paleatuspresent some characteristics related to its diet and lifestyle, such as the limited development of gill rakers and the abundance of taste buds. In addition, other special features associated with the environment and bimodal breathing were observed: scarce and absent mucous cells (MCs) in the gill filaments and branchial lamellae, respectively, and the localization of mitochondria‐rich cells (MRCs) covering the basal third of the branchial lamellae, which reduces the gill respiratory area. A peculiar finding in the gill epithelium of this armoured catfish was the presence of mononuclear cells with sarcomeres similar to myoid cells, whose functional importance should be determined in future studies. Finally, inC. paleatus, the interlamellar space of gill filaments is an important site for cell turnover and ionoregulation; the latter function is also performed by the branchial lamellae.
Age, growth, maturity and extinction risk of an exploited and endangered skate, Atlantoraja castelnaui, from off Uruguay and northern Argentina
Authors: Barbini Santiago A. , Sabadin David E. , Román Jorge M. , Scarabotti Pablo A. , Lucifora Luis O.
Published: June 2021

The spotback skate Atlantoraja castelnaui (Arhynchobatidae) is a large and threatened skate species subjected to fishing pressure, endemic to the Southwest Atlantic that occurs from Rio de Janeiro, Brazil, to San Jorge Gulf, Argentina. The age, growth, age at maturity and the maximum intrinsic rate of population increase rmax of A. castelnaui were studied using 152 specimens collected from off Uruguay and north Argentina (35°–42° S), between June 2013 and February 2020. Vertebrae from 143 individuals were used for ageing (females: n = 83, size range 404–1300 mm total length, TL; males: n = 60, size range 400–1270 mm TL). Maximum ages determined for females and males were 30 and 28 years, respectively. To fit growth models, non‐linear and Bayesian estimation approaches were considered. For the first approach, a set of four candidate growth (size‐at‐age) models were fitted: three‐parameter von Bertalanffy, two‐parameter von Bertalanffy with fixed L0, Gompertz and Logistic. In the second approach, von Bertalanffy, Gompertz and Logistic were fitted. For non‐linear estimation, model selection indicated that the entire set of candidate growth models were supported by the data. The von Bertalanffy was selected as the best model for Bayesian estimation. There were no differences in growth between sexes. For the sexes combined, the von Bertalanffy growth model by Bayesian method was considered the most adequate to describe the growth of A. castelnaui (growth mean parameters ± S.D.: L∞ = 1210.29 ± 40.68 mm; k = 0.12 ± 0.01 years−1; L0 = 179.20 ± 11.62 mm). The age at maturity was estimated at 16.21 and 14.04 years for females and males, respectively. The maximum intrinsic rate of population increase rmax was estimated as 0.252 years−1. Life‐history traits and rmax provided in the present study suggest that this species has a relatively low productivity and may be vulnerable to an intense fishing pressure.
Chemical, microbiological, sensory, and rheological properties of fresh goat milk cheese made by different starter cultures during storage
Authors: Pappa Eleni C. , Kondyli Efthymia , Bosnea Loulouda , Malamou Evdokia , Vlachou Anna‐Maria
Published: June 2021

Fresh soft goat milk cheese was manufactured by two different starter cultures, a mixture consisting of mesophilic and thermophilic microorganisms, that is, Lactococcus Lactis subsp.cremoris, Lactococcus Lactis subsp. lactis and Streptococcus thermophilus (cheese A) and a mesophilic one containing Lactococcus Lactis subsp. cremoris and Lactococcus Lactis subsp. lactis(cheese B). The cheesemaking technology included milk pasteurization, starter culture incubation, milk clotting by liquid rennet and salting in brine containing 15% w/w NaCl. The cheeses were matured for 5 days at 16–17°C and then were packaged in shrink polyethylene bags under vacuum and transferred to cold room (3–4°C) for storage. The composition, microbiological, organoleptic and rheological properties of cheeses were investigated. Cheese microbiota was dominated by mesophilic lactobacilli and cocci. Yeasts and molds were found at the end of storage (60‐day) resulting in the gradual spoilage of cheeses. All cheeses received low scores for hardness while they were very much appreciated for their organoleptic properties. Cheese A presented lower levels of total volatile compounds at 5 days but higher at 60 days than cheese B.

Practical Applications

It is widely known that goat milk has high nutritional properties. In Greece, goat milk is usually added in sheep milk in order to produce protected designation of origin and other traditional cheeses. Greek goat milk cheeses are usually white—brined or hard cheeses and they are produced in small scale. The aim of the present study was to investigate the cheesemaking technology of fresh soft goat milk cheese and evaluate the influence of using different cultures on the chemical, microbiological, sensory and rheological properties of this cheese. The results have shown that a good quality fresh goat cheese can be manufactured with shelf life up to 60 days and mesophilic or mixed thermophilic–mesophilic cultures can be used.
Safety and effectiveness of ustekinumab in Crohn's disease: Interim results of post‐marketing surveillance in Japan
Authors: Yokoyama Seiji , Asano Teita , Nagano Katsumasa , Tsuchiya Hiroaki , Takagishi Masayuki , Tsujioka Shigeharu , Miura Naomi , Matsumoto Takayuki
Published: June 2021

Background and Aim

Ustekinumab, a human anti‐interleukin‐12/23 monoclonal antibody, has been approved in Japan for the treatment of Crohn's disease. Here, we report the findings from an 8‐week interim analysis of post‐marketing surveillance to evaluate the safety and effectiveness of ustekinumab in Japanese patients with Crohn's disease.

Methods

Patients initiating ustekinumab treatment were prospectively evaluated from May 2017 to June 2020 at 91 medical centers in Japan. Adverse drug reactions (ADRs) and serious ADRs (SADRs) were monitored. Effectiveness was evaluated by clinical response, clinical remission, and changes in Crohn's Disease Activity Index (CDAI) and C‐reactive protein (CRP) from baseline to week 8. Presence of perianal disease was documented at baseline and week 8.

Results

In total, 341 patients were enrolled in the study, of which 339 were included in the safety analysis while 334 were included in the effectiveness analysis. The overall incidences of ADRs and SADRs were 5.3% and 2.1%, respectively. Worsening of Crohn's disease was the most common event. The clinical response and clinical remission rate at week 8 were 40.0% and 48.5%, respectively. Significant improvements in CDAI and serum CRP (P < 0.001) were observed at week 8. CDAI decreased significantly (mean difference: −31.4; 95% confidence interval: −61.1, −1.7; P = 0.038) in biologics‐naïve patients versus patients who had received two or more biologics.

Conclusions

This 8‐week interim analysis of the real‐world study confirmed the effectiveness of ustekinumab‐based therapy in Japanese patients with Crohn's disease. No new safety concerns were found during 8‐week induction period in the Japanese clinical settings.
Chronic disease health literacy in First Nations people: A mixed methods study
Authors: Rheault Haunnah , Coyer Fiona , Bonner Ann
Published: June 2021

Aim

To explore chronic disease education, self‐management and health literacy abilities from First Nations Australian adults with chronic disease through the integration of qualitative and quantitative findings.

Background

Chronic disease management requires good health literacy abilities to manage long‐term health needs. First Nations people have a higher burden of chronic disease although little is known regarding chronic disease health literacy of First Nations people.

Design

A concurrent embedded mixed methods study reported using the Consolidated Criteria for Reporting Qualitative Research guidelines.

Methods

Data were collected from First Nations people with one or more chronic diseases living in remote Australia between February–November 2017. Quantitative data (n = 200) were collected using the Health Literacy Questionnaire along with demographic and health data. Qualitative data (n = 20) were collected via face‐to‐face interviews to examine chronic disease education and self‐management experiences. Data were analysed separately then integrated to develop meta‐inferences.

Results

Poor communication from healthcare providers coupled with low health literacy abilities is a major barrier to both active and successful management of chronic disease. Communicating in medical jargon resulted in individuals being placed in a power differential causing lack of trust and relationship breakdowns with healthcare providers affecting active chronic disease self‐management. The perception of inevitability and ambivalence towards chronic disease and the notion of futility towards self‐management were concurred with the low level of active engagement in health care.

Conclusions

Yarning is an important strategy used by First Nations people for communication. For nurses, understanding and developing skills in yarning will facilitate cultural safety, communication and understanding about chronic disease self‐management in contexts where health literacy abilities are challenged.

Relevance to Clinical Practice

Using yarning, and plain language visual aids, and teach‐back will readdress the power differential experienced by First Nations people and may also improve understanding of chronic disease self‐management.
The development of the Western Australian Haemodialysis Vascular Access Complexity instrument
Authors: Coventry Linda L. , Hosking Jon , Coral Evelyn , Jenkins Mark , Salgado Kent Chandra P. , Chan Doris , Lim Wai , Twigg Diane E. , Rickard Claire M.
Published: June 2021

Background

The Western Australian Haemodialysis Vascular Access Classification instrument was developed to classify the cannulation complexity of the arteriovenous fistula or arteriovenous graft as simple, challenging, or complex. Although the instrument was developed by experts in haemodialysis nursing, the instrument had not undergone formal validity or reliability testing.

Objectives

Evaluate the Western Australian Haemodialysis Vascular Access Classification instrument for content validity, interrater and test–retest reliability.

Design

Prospective cohort study.

Participants

Content validity was assessed by haemodialysis nursing experts (n = 8). The reliability testing occurred in one in‐centre and one satellite haemodialysis unit in Western Australia from September to November 2019. Reliability testing was performed by 38 haemodialysis nurses in 67 patients receiving haemodialysis and 247 episodes of cannulation.

Measurements

Interrater and test–retest reliability assessment was conducted using κ, adjusted κ, Bland–Altman plots, intraclass correlation coefficient and Pearson's correlation coefficient.

Results

The final version of the instrument (n = 20 items) had individual item‐level content validity indices ranging from 0.625 to 1.00 with a scale‐level content validity index of 0.89. For both interrater (n = 172 pairs) and test–retest (n = 101 pairs), most individual variables had excellent adjusted κ (n = 33 variables), some fair to good agreement (n = 6 variables) and one variable with poor agreement. The classification of simple, challenging and complex demonstrated adjusted κ of fair to good, to excellent agreement for interrater reliability with lower levels of agreement for test–retest reliability.

Conclusions

This instrument may be used to match a competency‐assessed nurse to perform the cannulation thereby minimising the risk of missed cannulation and trauma.
Temperature and salinity adaptability of the coral reef topshell Tectus pyramis
Authors: Ou Zekui , Liu Wenguang , He Maoxian
Published: June 2021

Topshell Tectus pyramis is a coral reef snail of economic and ecological value. This study assessed temperature and salinity tolerance in T. pyramis and the interaction between temperature and salinity on metabolism. The adaptability of T. pyramis was assessed with mortality, respiration, and nitrogen excretion. This study found that snail (T. pyramis) with body sizes of width 60.30 ± 3.46, 40.12 ± 2.34, and 20.02 ± 1.15 mm tolerated temperatures of 15–35, 15–35, and 20–30°C and salinity of 13–38, 18–38, and 23–33‰, respectively. It demonstrates that larger snails can adapt better to variations in temperature and salinity. Temperature and salinity have a significant effect on the metabolism of snails. Smaller snails have a higher metabolism and are more sensitive to changes in temperature and salinity. Overall, results suggest that seawater with 30°C temperature and 33‰ salinity was suitable for T. pyramis.
Exploring attributions of causality for child undernutrition: Qualitative analysis in Lusaka, Zambia
Authors: Lufumpa Nakawala , Lavis Anna , Caleyachetty Rishi , Henry Michael , Kabombwe Sheena , Manaseki‐Holland Semira
Published: June 2021

Child undernutrition is responsible for 45% of all under‐five deaths in low‐ and middle‐income countries (LMICs) and numerous morbidities. Although progress has been made, high levels of child undernutrition persist in Zambia. Existing studies have explored primary caretakers' (PCs) explanatory models of child undernutrition in LMICs, without comparison with those of health care providers (HCPs). This paper examines and compares the perceived causes of child undernutrition among PCs and HCPs in Zambia. We conducted a qualitative study, using semistructured one‐to‐one and group interviews, with 38 PCs and 10 HCPs to explore their perceptions of child undernutrition and its perceived causes in Lusaka district, Zambia. Interview data were analysed with thematic analysis. Our findings indicate that PCs and HCPs in Lusaka district have divergent explanatory models of child undernutrition and perceive parental agency differently. In divergently framing how they conceptualise undernutrition and who is able to prevent it, these models underpin different attributions of causality and different opportunities for intervention. PCs highlighted factors such as child food preferences, child health, and household finances. Contrarily, HCPs stressed factors such as ‘improper feeding’, only highlighting factors such as wider economic conditions when these impacted specifically on health care services. One factor, identified by both groups, was ‘inadequate mothering’. To accelerate the reduction of child undernutrition, interventions must address divergences between PCs and HCPs' explanatory models. Additionally, attention needs to be paid to how wider socio‐economic and cultural contexts not only impact childhood undernutrition but shape attributions of causality.
Invasive aspergillosis due to Aspergillus cryptic species: A prospective multicentre study
Authors: Imbert Sebastien , Cassaing Sophie , Bonnal Christine , Normand Anne‐Cecile , Gabriel Frederic , Costa Damien , Blaize Marion , Lachaud Laurence , Hasseine Lilia , Kristensen Lise , Guitard Juliette , Schuttler Christine , Raberin Helene , Brun Sophie , Hendrickx Marijke , Piarroux Renaud , Fekkar Arnaud
Published: June 2021

Objectives

Aspergillus cryptic species are increasingly recognised causes of Aspergillus diseases, including life‐threatening invasive aspergillosis (IA). However, as their accurate identification remains challenging in a routine practice, few is known from a clinical and epidemiological perspective. Recently, the MSI application has emerged as a powerful tool for the detection and identification of Aspergillus cryptic species. We aimed to use to the network of users of the MSI application to conduct a multicentre prospective screening of Aspergillus cryptic species‐related IA and analyse their epidemiological, clinical and mycological characteristics.

Methods

Over a 27‐month period, the clinical involvement of 369 Aspergillus cryptic isolates, from 13 French and Danish MSI application users, was prospectively analysed. Species identification was confirmed by DNA‐sequencing and antifungal susceptibility testing was performed using EUCAST reference method. Fifty‐one A fumigatus sensu stricto invasive cases were also analysed.

Results

Fifteen cryptic isolates were responsible of IA. Eight species were involved, including 5 cases related to the species A sublatus. These species showed high rate of in vitro low susceptibility to antifungal drugs. In comparison with A fumigatus sensu stricto invasive cases, pre‐exposure to azole drugs was significantly associated with cryptic IA (P = .02).

Discussion

This study brings new insights in cryptic species related IA and underlines the importance to identify accurately at the species level these Aspergillus isolates. The increasing use of antifungal drugs might lead in the future to an epidemiologic shift with an emergence of resistant isolates involved in IA.
Contributions of the international plant science community to the fight against infectious diseases in humans—part 2: Affordable drugs in edible plants for endemic and re‐emerging diseases
Authors: He Wenshu , Baysal Can , Lobato Gómez Maria , Huang Xin , Alvarez Derry , Zhu Changfu , Armario‐Najera Victoria , Blanco Perera Aamaya , Cerda Bennaser Pedro , Saba‐Mayoral Andrea , Sobrino‐Mengual Guillermo , Vargheese Ashwin , Abranches Rita , Alexandra Abreu Isabel , Balamurugan Shanmugaraj , Bock Ralph , Buyel Johannes F. , da Cunha Nicolau B. , Daniell Henry , Faller Roland , Folgado André , Gowtham Iyappan , Häkkinen Suvi T. , Kumar Shashi , Sathish Kumar Ramalingam , Lacorte Cristiano , Lomonossoff George P. , Luís Ines M. , K.‐C. Ma Julian , McDonald Karen A. , Murad Andre , Nandi Somen , O’Keef Barry , Parthiban Subramanian , Paul Mathew J. , Ponndorf Daniel , Rech Elibio , Rodrigues Julio C.M. , Ruf Stephanie , Schillberg Stefan , Schwestka Jennifer , Shah Priya S. , Singh Rahul , Stoger Eva , Twyman Richard M. , Varghese Inchakalody P. , Vianna Giovanni R. , Webster Gina , Wilbers Ruud H. P. , Christou Paul , Oksman‐Caldentey Kirsi‐Marja , Capell Teresa
Published: June 2021

The fight against infectious diseases often focuses on epidemics and pandemics, which demand urgent resources and command attention from the health authorities and media. However, the vast majority of deaths caused by infectious diseases occur in endemic zones, particularly in developing countries, placing a disproportionate burden on underfunded health systems and often requiring international interventions. The provision of vaccines and other biologics is hampered not only by the high cost and limited scalability of traditional manufacturing platforms based on microbial and animal cells, but also by challenges caused by distribution and storage, particularly in regions without a complete cold chain. In this review article, we consider the potential of molecular farming to address the challenges of endemic and re‐emerging diseases, focusing on edible plants for the development of oral drugs. Key recent developments in this field include successful clinical trials based on orally delivered dried leaves of Artemisia annua against malarial parasite strains resistant to artemisinin combination therapy, the ability to produce clinical‐grade protein drugs in leaves to treat infectious diseases and the long‐term storage of protein drugs in dried leaves at ambient temperatures. Recent FDA approval of the first orally delivered protein drug encapsulated in plant cells to treat peanut allergy has opened the door for the development of affordable oral drugs that can be manufactured and distributed in remote areas without cold storage infrastructure and that eliminate the need for expensive purification steps and sterile delivery by injection.
The culturally intelligent way of acculturating: Examining cultural intelligence and acculturation orientations among foreign workers in the Danish context of reception
Authors: Ozer Simon , Schwartz Seth J.
Published: June 2021

In contemporary globalized societies, the number of foreign workers is increasing, resulting in greater intercultural contact and adaptation. Foreign workers apply their cultural intelligence when adapting to and working in multicultural environments, resulting in affiliations with both their cultural heritage and their destination cultural stream. We examined foreign workers’ (N = 264) intercultural adaptation in the globalized context of Denmark. We found that cultural intelligence was directly and positively linked with adaptable work performance. Furthermore, cultural intelligence was indirectly and negatively associated with sociocultural adaptation difficulties through endorsement of Danish culture. Likewise, perceived negative context of reception was indirectly and positively associated with sociocultural adaptation difficulties through low endorsement of Danish culture. Additionally, perceived stress predicted adaptable work performance, whereas perceived context of reception and sociocultural adaptation difficulties did not. Overall, our results suggest involvement in the destination culture as a culturally intelligent way of applying one’s cultural capabilities, suggesting that the perceived context of reception is of great importance for helping foreign workers adapt to their destination cultural environments.
Toward a sociology of global comparative placemaking
Authors: Chica Christina Marie
Published: June 2021

I call for a globally informed sociology of comparative placemaking that integrates historical and contemporary processes and includes the ephemeral, institutional, and personal. By placemaking, I am referring to the explicit or tacit cooperation among people to create, maintain, and give meaning to places in space through bodily occupation given differential resources and constraints. I review select place, space, and community‐based literature about urban, Black, migrant, LGBTQ, and international populations to think about how we can build upon and integrate multiple theoretical, methodological, and epistemological insights to form an explicit placemaking research agenda. A US focus on neighborhoods contrasts with a comparative examination of global urban networks, social polarization, and transformation of the built environment in the interdisciplinary field of global urban studies (Ren, 2018). I argue for a placemaking research agenda that bridges insight from US Urban Sociology with Global Urban Studies to consider how various structures and actors constrain and facilitate place projects. With a globally reaching and comparatively informed sociology of placemaking, we can illuminate our multi‐structured story of place and agency in context. We can answer questions about how and why we co‐create and are simultaneously disciplined by the process of creation.
Building Pathology and COVID-19: A Literature Review and Commentary on Field Hospital Setting
Authors: Mungmunpuntipantip Rujittika , Wiwanitkit Viroj
Published: June 2021

In 2019, there was an emerging disease, namely Coronavirus 2019 (COVID-19). This disease firstly emerged in Asia before there was a worldwide spreading. COVID-19 is highly contagious. The pandemic results in more than 100 million infections worldwide (by the end of January 2021). Each country has to have a good public health plan to correspond with the increasing number of the patient. To correspond with the rapid increase in the number of COVID-19 patients, finding for sufficient space for patient care is needed. The presently available number of hospitals might be limited and it usually requires an urgent setting of the new building for management of the situation. The field hospital is usually set. In this work, the authors performed a retrospective literature review to summarize the available data on building pathology and COVID-19. The aim of the study is about the quality of the field hospital buildings and the defects in the buildings. The standard databases, SCOPUS and PubMED are used for literature searching. The derived publications are summarized and extracted for a conclusion. According to the literature analysis, there are very few publications on the topic of building pathology of a field hospital for COVID-19 containment. The role of field hospital in outbreak management is confirmed in thee literature. However, the specific report regarding building pathology of field hospital is limited. The newly constructed field hospital is usually in the rapid emergency mode. Based on the present analysis, it can show that there is a lack of concern on building pathology of the field hospital. Due to the rapid construction of field hospitals for COVID-19 outbreak management, the quality control and standardization are important. Further researches on the building pathology and quality management of field hospital are recommended.
Hydrogen-Enriched Biogas Premixed Charge Combustion and Emissions in Direct Injection and Indirect Injection Diesel Dual Fueled Engines: A Comparative Study
Authors: Bui Van Ga , Bui Thi Minh Tu , Hoang Anh Tuan , Nižetić Sandro , Nguyen Thi Thanh Xuan , Vo Anh Vu
Published: June 2021

This paper presents a comparative study on combustion and emissions of hydrogen-enriched biogas premixed charge direct injection dual-fuel (DIDF) engine and indirect injection dual-fuel (IDIDF) engine. The results show that the IDIDF engine outperforms the DIDF engine in terms of higher indicative engine cycle work (Wi) and lower emissions of CO, soot, and noise, but the disadvantage is higher NOx emission. Under the same fueling condition, the IDIDF engine’s Wi is on average 6% higher than that of the DIDF engine, but the NOx concentration in the combustion products of the IDIDF engine is 1.5 times higher than that of the DIDF engine. The IDIDF engine creates the stratified mixture distribution with higher O2 concentration in the auxiliary combustion chamber, which is favorable for auto-ignition and reduces the ignition delay. The biogas composition affects slightly CO and soot emissions, but significantly affects NOx emission. When the methane composition in biogas increases from 60% to 80%, the soot volume fraction is approximately 0.1 ppm in both types of combustion chambers, the CO concentration varies from 1.4% to 1.8%, and the NOx concentration varies from 3000 to 5000 ppm in the case of IDIDF engine and 2500–4500 ppm in the case of DIDF engine. For both types of dual-fuel engines, when engine speed increases, CO concentration and the soot volume fraction increase, while Wi and NOx concentration decrease.
Identification and Estimation of Damage Severity in a Turbine Blade Packet Using Inverse Eigen-Value Analysis—A Numerical Study
Authors: Chatterjee Animesh
Published: June 2021

Turbine blades are critical machine components in power plants and aerospace turbo engines. Failure of these blades in operation leads to catastrophic damages as well as high cost of maintenance and repair. Blades are often assembled in packets with lacing wire or shroud ring interconnections. Natural frequencies of the bladed packets are designed in a specific range to avoid possible resonant stresses. However, frequent damages during operation alter the stiffness of the blade-packet assembly and change the eigen-spectrum. A numerical study is presented in this work, where it is demonstrated that characteristic changes in eigen-spectrum can identify both severity and location of such damages. The work employs matrix perturbation theory on the eigen-value problem, formulated from the lumped-parameter modeling of the blade packet. Damage is considered as a perturbation in the stiffness matrix with damage severity acting as the perturbation parameter. First, a graphical pattern recognition method, and then, a damage proximity index evaluation method is suggested for damage identification. Further, an estimation algorithm for damage severity is presented with numerically simulated computations, which demonstrates that the methods can exactly identify the damage location and, with very little error, can estimate the damage severity.
Design and Analysis of Nonlinear Controller for a Standalone Photovoltaic System Using Lyapunov Stability Theory
Authors: Kumar Narendra , Sharma Aman
Published: June 2021

This paper presents the Lyapunov stability theory-based nonlinear controller design for a standalone photovoltaic (PV) system. The comparative analysis of different nonlinear controllers is also carried out. Due to the nonlinear I-V characteristics of photovoltaic systems, conventional hill-climbing methods like Perturbate and Observe and Incremental Conductance do not show reliable tracking of maximum power under various uncertainties. Therefore, these methods require nonlinear tools to meet control objectives and design specifications. Out of various nonlinear controlling techniques, the one presented in this paper is the sliding mode approach for maximum power point tracking (MPPT). In the context of Lyapunov stability theory, the sliding mode approach uses a switching manifold. In this approach, the system trajectories are made to follow the sliding surface and remain there forever to ensure the stability of equilibrium points. Two types of sliding mode controllers have been simulated, namely, conventional—sliding mode controller (CSMC) and terminal—sliding mode controller (TSMC). The results are analyzed and compared scientifically on various performance parameters including duty cycle ratio, ideal and PV output power, and time taken for error convergence, under varying dynamic conditions. All the control algorithms are developed in matlab/Simulink.
The Influence of an Impedance Obstacle on the Acoustic Field Inside a Rectangular Room
Authors: Szemela Krzysztof , Rdzanek Wojciech
Published: June 2021

The problem of sound propagation inside a rigid-walled room containing a rectangular obstacle was solved by dividing an acoustic field into subregions and using the continuity conditions. Acoustic waves were generated by a point source. The formulas valid for an impedance obstacle extending from a room floor to its ceiling were obtained. The considered obstacle can model such elements as a ventilation shaft, furniture, or construction pillar. The solution was expressed in the form of convergent series. To obtain accurate results, the error resulting from the use of truncated series was controlled. Additionally, to check the correctness of the proposed solution and its computer implementation, the results obtained for a negligibly small obstacle were compared with those given by the empty room model. An excellent agreement was achieved which proves a high accuracy of the used methodology. The numerical analysis shows that the calculation time of acoustic pressure in a part of an empty room can be significantly reduced using the obtained solution. An appropriate source location for noise reduction was found. The distribution of acoustic field was illustrated and some conclusions were formulated. The changes in acoustic field due to the presence of an obstacle were predicted and discussed.
Mechanism of Crack Initiation and Propagation of Re-Entrant Auxetic Honeycombs Under Thermal Shock
Authors: Li Z. , Wang B. L. , Wang K. F.
Published: June 2021

Thermal shock multiple cracking behaviors of re-entrant auxetic honeycombs with a negative Poisson’s ratio are investigated, and the crack initiation and propagation behavior are discussed. An effective macro continuum model is developed to detect the effects of cracking density and microstructures of auxetic honeycombs on the thermal stress and intensity. The microscale tensile stresses in the struts ahead of the crack as functions of the corresponding thermal stress intensity factor (SIF) at the macroscale are evaluated by employing a macro–micro model. Then, a lower-bound method is proposed to assess the critical thermal load of auxetic honeycombs by combining the macro-micro model and the macro continuum model. A significant increase in both transient thermal stress and intensity as the growing cell-wall angle is demonstrated. Results for the maximum thermal SIF as well as the maximum tensile stress in the middle of cracks are calculated as functions of crack density and length. With the identical SIF, the microscale tensile stresses ahead of the crack in honeycombs with smaller cell-wall angles are greater than that in mediums with larger angles due to the more significant crack tip opening displacement. Critical thermal load prediction reveals that the honeycombs with smaller cell-wall angles generally possess more excellent thermal shock resistance. Also, the varying failure modes of different auxetic honeycomb strips under specific thermal load are predicted. The corresponding mechanisms of crack initiation and propagation are revealed.
SSVEP-Based Brain-Computer Interface for Part-Picking Robotic Co-Worker
Authors: Li Yao , Kesavadas Thenkurussi
Published: June 2021

One of the expectations for the next generation of industrial robots is to work collaboratively with humans as robotic co-workers. Robotic co-workers must be able to communicate with human collaborators intelligently and seamlessly. However, industrial robots in prevalence are not good at understanding human intentions and decisions. We demonstrate a steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) which can directly deliver human cognition to robots through a headset. The BCI is applied to a part-picking robot. The BCI sends decisions to the robot while operators visually inspecting the quality of parts. The BCI is verified through a human subject study. In the study, a camera by the side of the conveyor takes photos of each industrial part and presents it to the operator automatically. When the operator looks at the photo, the electroencephalography (EEG) is collected through the BCI. The inspection decision is extracted through SSVEPs in EEG. When a defective part is identified by the operator, the signal is communicated to the robot, which locates the defective part by a second camera and removes it from the conveyor. The robot can grasp various part with our random grasp planning algorithm (2FRG). We have developed a CNN-CCA model for SSVEP extraction. The model is trained on a dataset collected in our offline experiment. Our approach outperforms the existing CCA, CCA-SVM, and PSD-SVM models. The CNN-CCA model is further validated in an online experiment and achieved 93% accuracy in identifying and removing defective parts.
Design Synthesis Through a Markov Decision Process and Reinforcement Learning Framework
Authors: Ororbia Maximilian E. , Warn Gordon P.
Published: June 2021

This article presents a framework that mathematically models optimal design synthesis as a Markov Decision Process (MDP) that is solved with reinforcement learning. In this context, the states correspond to specific design configurations, the actions correspond to the available alterations modeled after generative design grammars, and the immediate rewards are constructed to be related to the improvement in the altered configuration’s performance with respect to the design objective. Since in the context of optimal design synthesis the immediate rewards are in general not known at the onset of the process, reinforcement learning is employed to efficiently solve the MDP. The goal of the reinforcement learning agent is to maximize the cumulative rewards and hence synthesize the best performing or optimal design. The framework is demonstrated for the optimization of planar trusses with binary cross-sectional areas, and its utility is investigated with four numerical examples, each with a unique combination of domain, constraint, and external force(s) considering both linear-elastic and elastic-plastic material behaviors. The design solutions obtained with the framework are also compared with other methods in order to demonstrate its efficiency and accuracy.
Nonlinear Finite Element Load-Displacement Model and Analysis of Circular-Axis Hinge, Self-Similar Mechanism With Large Out-of-Plane Motion
Authors: Munteanu M. Gh. , Lobontiu N.
Published: June 2021

This research studies the large-displacement response of a fractal-architecture mechanism with circular-axis flexible hinges by formulating an efficient and accurate nonlinear finite element model. Two three-dimensional line elements are proposed whose nodal degrees-of-freedom include the three spatial Tait–Bryan angles. The nonlinear finite element is generated using the minimum potential energy condition for the entire deformed structure in a non-incremental approach. The error does not depend on the number of load steps since one step is sufficient to achieve the final, deformed state. The method is applied to predict the nonlinear, large, out-of-plane displacement of the fractal-hinge compliant mechanism. The model predictions are validated by finite element code simulation and experimental testing. The nonlinear finite element force-displacement data coincide with the linear compliance model predictions of Lobontiu et al. (2019, “Stiffness Design of Circular-Axis Hinge, Self-similar Mechanism With Large Out-of-Plane Motion,” ASME J. Mech. Des., 141(9), p. 092302) for approximately one-fourth lower portion of the load range and display the expected hardening-spring features for the load range remainder.
Optimization of Design Margins Allocation When Making Use of Additive Remanufacturing
Authors: Al Handawi Khalil , Panarotto Massimo , Andersson Petter , Isaksson Ola , Kokkolaras Michael
Published: June 2021

Requirement changes can result in substantial overdesign because of the way design margins are allocated at the beginning of the design process. We present a design optimization method for minimizing overdesign by making use of additive remanufacturing and recently defined constituents of design margins (buffer and excess). The method can be used to obtain a set of design decisions for different changing requirement scenarios. We demonstrate our method by means of a turbine rear structure design problem where changes in the temperature loads are met by depositing different types of stiffeners on the outer casing. The results of the case study are visualized in a tradespace, which allows for comparison between sets of optimal, flexible, and robust designs. Results show that the optimized set of design decisions balances flexibility and robustness in a cost-effective manner.
Design Control and Performance of a Cable-Driving Module With External Encoder and Force Sensor for Cable-Driven Parallel Robots
Authors: An Hao , Zhang Yongqing , Yuan Han , Xu Wenfu , Wang Xin
Published: June 2021

Cable-driven parallel robots (CDPRs) have the characteristic of easy deployment, which endows CDPRs with flexible workspace, freely configurable degrees-of-freedom (DOFs), and various configurations, greatly expanding their range of applications. Modular design provides excellent convenience and feasibility for deployment, which is a crucial issue of CDPR design. A highly integrated cable-driving module is designed in this paper, which includes the winding bobbin, servo motor, force sensor, external encoder, electromagnetic brake, as well as other devices. Experiments show that the maximum cable length control error is less than 0.16%, and the maximum cable tension control error is less than 8% in the back-and-forward rotation test. Furthermore, a CDPR with eight cables and six DOFs is constructed rapidly using the proposed module, whose dimension is 850 × 850 × 650 mm3. Results show that the robot’s trajectory errors are all less than 4.5 mm, and the root-mean-square-error (RMSE) is 2.1 mm. Besides, the compliance control experiments show that the robot’s tracking error in an impedance control mode is less than 2 mm, and the RMSE is 0.95 mm. Moreover, the dragging force in a teaching mode is less than 2.5 N. The proposed integrated cable-driving module could be helpful for the modular design and deployment of CDPRs.
Shell-Side Flow Condensation Heat Transfer on Three-Dimensional Enhanced Surface
Authors: Li Wei , Yang Desong , Chen Jingxiang , Sun Zhichuan , Wang Jiacheng , Ayub Zahid
Published: June 2021

An experimental investigation of shell-side flow condensation was performed on three-dimensional surface enhanced tubes, including a herringbone micro-fin tube and a newly developed 1-EHT tube. An equivalent plain tube was also tested for performance comparison. All the test tubes had similar geometry parameters, i.e., inner diameter 11.43 mm and outer diameter 12.7 mm. The outer shell diameter was 24.5 mm with a wall thickness of 0.6 mm. Tests were conducted using R410A as the working fluid at a dew point of 45 °C. The mass flux range of 10–55 kg/(m2 · s) with an inlet quality of 0.8 and an outlet quality of 0.1. Experimental results showed that the plain tube exhibited a better condensation heat transfer performance. Moreover, the mass flux had a significant influence on the heat transfer coefficient for shell-side condensation. A new prediction model based on the Cavallini’s equation was developed to predict the condensing coefficient where the mean absolute error is less than 4%.
Investigating phoneme-dependencies of spherical voice directivity patterns
Authors: Pörschmann Christoph , Arend Johannes M.
Published: June 2021

Dynamic directivity is a specific characteristic of the human voice, showing time-dependent variations while speaking or singing. To study and model the human voice's articulation-dependencies and provide datasets that can be applied in virtual acoustic environments, full-spherical voice directivity measurements were carried out for 13 persons while articulating eight phonemes. Since it is nearly impossible for subjects to repeat exactly the same articulation numerous times, the sound radiation was captured simultaneously using a surrounding spherical microphone array with 32 microphones and then subsequently spatially upsampled to a dense sampling grid. Based on these dense directivity patterns, the spherical voice directivity was studied for different phonemes, and phoneme-dependent variations were analyzed. The differences between the phonemes can, to some extent, be explained by articulation-dependent properties, e.g., the mouth opening size. The directivity index, averaged across all subjects, varied by a maximum of 3 dB between any of the vowels or fricatives, and statistical analysis showed that these phoneme-dependent differences are significant.
Meta-learning-aided orthogonal frequency division multiplexing for underwater acoustic communications
Authors: Zhang Yonglin , Wang Haibin , Li Chao , Chen Desheng , Meriaudeau Fabrice
Published: June 2021

In this paper, a meta-learning-based underwater acoustic (UWA) orthogonal frequency division multiplexing (OFDM) system is proposed to deal with the environment mismatch in real-world UWA applications, which can effectively drive the model from the given UWA environment to the new UWA environment with a relatively small amount of data. With meta-learning, we consider multiple UWA environments as multi-UWA-tasks, wherein the meta-training strategy is utilized to learn a robust model from previously observed multi-UWA-tasks, and it can be quickly adapted to the unknown UWA environment with only a small number of updates. The experiments with the at-sea-measured WATERMARK dataset and the lake trial indicate that, compared with the traditional UWA-OFDM system and the conventional machine learning-based framework, the proposed method shows better bit error rate performance and stronger learning ability under various UWA scenarios.
Sport4Change: Adapting to COVID-19 Through Innovation
Authors: McSweeney Mitchell , Svensson Per G. , Naraine Michael L.
Published: June 2021

The case explores how Sport4Change will adapt its sport-for-development (SFD) programs in response to the current uncertainty presented by COVID-19. Being able to innovate program operations, implementation, and delivery is key to the success and long-term sustainability of Sport4Change, and changing program strategies needs to be done correctly given the organization’s varying locations around the world. Making such decisions requires consideration of the various contexts in which Sport4Change works, understanding diverse options to implement SFD through technological or remote means, and aligning remote delivery and operations with each SFD location and their in-person program focus and goals in order to come up with solutions to ensure SFD remains impactful during COVID-19.
Influence of Dimensional Effects on the Curie Temperature of Dy and Ho Thin Films
Authors: Devyaterikov D. I. , Proglyado V. V. , Zhaketov V. D. , Nikitenko Yu. V. , Kondrat’ev O. A. , Pashaev E. M. , Subbotin I. A. , Zverev V. I. , Kravtsov E. A. , Ustinov V. V.
Published: June 2021

The role of size effects in the formation of the magnetic structure of Dy and Ho thin films in absence of epitaxial strain is studied in this work. It was found that, for Dy in the temperature range between the Néel temperature and the Curie temperature of bulk Dy and, for Ho, in the temperature range between the Néel temperature and the temperature of phase transition into the conic phase, the temperature dependences of the period of magnetic helicoid in the bulk and film metals are similar. The character of the transition into the ferromagnetic phase in the Dy films changes at lower temperatures, and the transition into the commensurable conic phase in the Ho films is suppressed. This is explained exclusively by the influence of dimensional effects.
Intravenous immunoglobulin as a therapeutic option for patients with worsening COVID-19 under rituximab
Authors: Vasconcelos Joana , Portugal Rita , Torres Rita , Falcão Sandra
Published: June 2021

Severe cases of the new COVID-19 are being reported in immunosuppressed patients. The risk seems to depend on the type of immunosuppressive agents used and it is particularly important in patients under the long-lasting effect of rituximab. Information regarding the best therapeutic approach to these patients is scarce and further studies are needed. We present a case of a young woman with rheumatoid arthritis treated with rituximab (last administration 4 months before her admission). She presented with a deteriorating and prolonged SARS-CoV-2 infection, with persistent fever, significant elevation of inflammatory markers and radiological progression. Glucocorticoids and antibiotic therapy were initiated, with no response. Intravenous immunoglobulin was then used with a rapid and exuberant response, anticipating a promising role of this therapy in immunosuppressed patients with COVID-19 under the effect of rituximab.