bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimierung von Minibustaxiverkehren in Südafrika unter Einbindung von Geoinformationssystemen
Authors: Schlüter Jan , Sörensen Leif , Simons Johannes , Coetzee Justin
Published: January 2021

Das Minibustaxi ist eines der wichtigsten Mobilitätsangebote in Südafrika. Allerdings sind Informationen, wie Fahrpläne oder -zeiten, aufgrund der hohen Flexibilität gar nicht oder nur selten verfügbar. Die damit einhergehenden Ineffizienzen, auch im Hinblick auf eine Abstimmung mit anderen Mobilitätsangeboten, können ohne Dokumentation des Status quo nur schwer behoben werden. Deshalb zeigt dieser Artikel exemplarisch am Beispiel Kapstadts, dass bereits einfache Methoden die Abbildung des Minibustaxiverkehrsnetzes ermöglichen und damit die Grundlage für Optimierungsansätze schaffen. Die Datenerfassung mittels einer mobilen Anwendung und die darauffolgende Auswertung zeigen, dass Effizienzsteigerungen im Minibustaxiverkehr von rund 30 % realisierbar wären. Neben dem operativen und gesamtwirtschaftlichen Einspar‑/Ertragsmöglichkeiten kann zusätzlich die potenzielle CO2-Emissionseinsparung angebracht werden. Dieser Artikel leistet ein wichtiges Argument für Formalisierungsansätze, um Effizienzsteigerungen im Mobilitätssektor gegenüber dem Status quo auch politisch vorantreiben zu können.
Posterolateral epidural supra-C2-root approach (PESCA) for biopsy of lesions of the odontoid process in same sitting after occipitocervical fixation and decompression—perioperative management and how to avoid vertebral artery injury
Authors: Haas Patrick , Hauser Till-Karsten , Kandilaris Kosmas , Schenk Sebastian , Tatagiba Marcos , Adib Sasan Darius
Published: January 2021

This study aims to describe the posterolateral epidural supra-C2-root approach (PESCA), which might be a good alternative to the transoral, anterolateral, and other posterolateral approaches for biopsy of lesions of the odontoid process (OP). The preoperative planning of PESCA included computerized tomography (CT), CT-angiography, and three-dimensional reconstruction (if possible, even with three-dimensional print) to analyze the angle of the trajectory and the anatomy of the vertebral artery (VA). For PESCA, the patient is positioned under general anesthesia in prone position. In case of an osteolytic lesion with fracture of the OP, an X-ray is performed after positioning to verify anatomic alignment. In the first step, in case of instability and compression of the spinal cord, a craniocervical fusion and decompression is performed (laminectomy of the middle part of the C1 arc and removal of the lower part of the lateral C1 arc). The trajectory is immediately above the C2 root (and under the upper rest of the lateral part of C1 arc). Even if the trajectory is narrowed, it is possible to perform PESCA without relevant traction of the spinal cord. The vertical segment of V3 of the VA at the level of C2 is protected by the vertebral foramen, and the horizontal part of V3 is protected by the remnant upper lateral part of the C1 arc (in case of normal variants). PESCA might be a good choice for biopsy of selected lesions of the OP in same sitting procedure after craniocervical stabilization and decompression.
Income inequality and the quality of imports
Authors: Ciani Andrea
Published: January 2021

This paper studies the role of income inequality in the importing country as a determinant of export unit value and product quality estimated employing information on market shares and prices. Using detailed firm-level data, we find that higher inequality in the destination market is associated with lower unit value and product quality. Noticeably, the negative effect of inequality is stronger in richer destinations. Firm-level heterogeneous responses to market conditions explain changes in unit value and quality. Incumbent exporting firms report lower unit value when income inequality increases, while entrants supply products of lower quality. All in all, our findings show that income inequality is a determinant of import demand which ultimately induces quality and unit value differentials across markets.
Asking future doctors: what support options do medical students want to cope with medical school?
Authors: Ehring E. , Frese T. , Fuchs S. , Dudo K. , Pukas L. , Stoevesandt D. , Watzke S.
Published: January 2021

Aim

Medical school is demanding, and research aimed at improving the mental health of medical students is scarce. No quantitative study about which specific measures students actually prefer to reinforce their health has been performed yet. The aim of this survey is to find out which types of support should be given to medical students according to students’ own perspectives.

Subject and methods

A classroom survey of medical students (N = 1108, years 1–5) was carried out regarding various support options and depressive symptoms. The statistical analysis was finalized using chi-square tests, t-tests, and the Kolmogorov–Smirnov test.

Results

The support options with the highest average scores were accessible sports classes, desire for free water/fruit during lectures, and a clear study structure. Groups to exchange experiences with, including social media groups, were favored less. Depressive symptoms in students correlated with a higher level of applicability of support options.

Conclusion

Medical students require supportive study conditions. Specific subgroups of medical students could not be correlated to a particular support program. Thus, we need a support program that addresses students’ wishes, not a program based on feasibility, staff interests or passions.
Spatial variation in macrobenthic assemblages and their relationship with environmental factors in the upstream and midstream regions of the Heihe River Basin, China
Authors: Wang Yu , Liu Juan-Juan , Liu Wei , Feng Qi , Li Bao-long , Lu Han , Wang Shuang
Published: January 2021

The Heihe River is a typical inland river under increasing anthropogenic pressure. To explore the characteristics of the macrobenthic assemblages and their relationships with environmental factors in the upstream and midstream regions of this basin, abiotic conditions and macrobenthic assemblages were investigated in the summers of 2018 and 2019. A total of 50 species were collected, and Arthropoda and mollusks were the dominant groups. A significant increase in standing stock was observed from the upstream to midstream, and predators (PR) were the main functional feeding group. A one-way analysis of variance (ANOVA) revealed that the Shannon-Wiener index and Margalef’s index values significantly differed at the spatial scale (P < 0.05). A redundancy analysis (RDA) and Pearson correlation analysis showed that the spatial heterogeneity of the macrobenthos was influenced by the biochemical oxygen demand (BOD5), water temperature (WT), total nitrogen (TN), salinity, electrical conductivity (EC), total dissolved solids (TDS), dissolved oxygen (DO), and potassium permanganate index (CODMn) (P < 0.05). The spatial variation of macrobenthos was mainly governed by natural conditions and human disturbances.
Elevated turbulent and double-diffusive nutrient flux in the Kuroshio over the Izu Ridge and in the Kuroshio Extension
Authors: Nagai Takeyoshi , Rosales Quintana Gandy Maria , Durán Gómez Gloria Silvana , Hashihama Fuminori , Komatsu Kosei
Published: January 2021

While the Kuroshio is known to be a nutrient stream, as these nutrients are in dark subsurface layers, they are not immediately available for photosynthesis unless they are supplied to the sunlit surface layers. Recent microstructure observations have revealed that strong diapycnal mixing caused by the Kuroshio flowing over topographic features and double diffusion in the subsurface layers of the Kuroshio. However, it is still unclear how much nutrient flux can be provided by these microscale mixing processes. In this study, using an autonomous microstructure float and nutrient samplings, nutrient flux caused by the Kuroshio over the Izu Ridge, and that caused by double diffusion in the Kuroshio Extension are quantified. The nitrate diffusive flux is estimated to be $$>1 \,\hbox {mmol} \,\hbox {N}\,\hbox {m}^{-2}\hbox {day}^{-1}$$

>
1

mmol

N

m

-
2

day

-
1

over a distance, 20–30 km near the Izu Ridge and $$>0.1 \,\hbox {mmol} \,\hbox {N}\, \hbox {m}^{-2}\hbox {day}^{-1}$$

>
0.1

mmol

N

m

-
2

day

-
1

, which persists further downstream direction over 100 km along the Kuroshio, increasing the subsurface chlorophyll-a concentration in the region 200 km downstream. The double-diffusion-induced nitrate flux is estimated to be 1-$$10 \,\hbox {mmol} \,\hbox {N} \,\hbox {m}^{-2}\hbox {day}^{-1}$$

10

mmol

N

m

-
2

day

-
1

in the pycnostad 26–$$26.5\,\hbox {kgm}^{-3}$$

26.5

kgm

-
3

of the Kuroshio Extension, suggesting that whether this double-diffusion-induced nutrient flux in the subsurface layers can ultimately contribute to surface primary production depends on additional eddy up- and northward fluxes.
Noise Reduction for Improvement of Ultrasonic Monitoring Using Coda Wave Interferometry on a Real Bridge
Authors: Wang Xin , Chakraborty Joyraj , Niederleithinger Ernst
Published: January 2021

Reinforced concrete bridges are iconic parts of modern infrastructure. They are designed for a minimum service life of 100 years. However, environmental factors and/or inappropriate use might cause overload and accelerate the deterioration of bridges. In extreme cases, bridges could collapse when necessary maintenance lacks. Thus, the permanent monitoring for structure health assessment has been proposed, which is the aim of structural health monitoring (SHM). Studies in laboratories have shown that ultrasonic (US) coda wave interferometry (CWI) using diffuse waves has high sensitivity and reliability to detect subtle changes in concrete structures. The creation of micro-cracks might be recognized at an early stage. Moreover, large-volume structures can be monitored with a relatively small number of US transducers. However, it is still a challenge to implement the CWI method in real SHM practical applications in an outdoor environment because of the complex external factors, such as various noise sources that interfere with the recorded signals. In this paper, monitoring data from a 36-m long bridge girder in Gliwice, Poland, instrumented with embedded US transducers, thermistors, and vibrating wire strain gauges, is presented. Noise estimation and reduction methods are discussed, and the influence of traffic, as well as temperature variation, are studied. As a result, the relative velocity variation of US waves following the temperature change with a very high precision of $$10^{-4} \%$$

10

-
4

%

is shown, and a good bridge health condition is inferred. The influence of lightweight real traffic is negligible. The study verified the feasibility of the implementation of the CWI method on real bridge structures.
Buckling of circular plates with functional grading in two directions
Authors: Fiorini Alessandro , Ruta Giuseppe
Published: January 2021

This short note considers thin circular plates, functionally graded in both axial and transverse directions and loaded in compression on the middle plane by a uniform axisymmetric load. The functional grading is based on recent literature on the subject and we deal with a direct problem for buckling, i.e., given the geometry of the plate and its constitutive properties, the critical load multiplier and the buckling mode are determined by a usual non-triviality condition. Original expressions are found in a nearly closed form and show that suitable functional grading, actually achievable in practice, may lead to gentle solutions. Numerical examples, physical interpretations and comments are provided.
Spatially localized vibrations in a rotor subjected to flutter
Authors: Nitti A. , Stender M. , Hoffmann N. , Papangelo A.
Published: January 2021

The current push toward lightweight structures in aerospace and aeronautical engineering is leading to slender design airfoils, which are more likely to undergo large deformation, hence experiencing geometrical nonlinearities. The problem of vibration localization in a rotor constituted by N coupled airfoils with plunge and pitch degrees of freedom subjected to flutter instability is considered. For a single airfoil, it is shown that depending on the system parameters, multiple static and dynamic equilibria coexist which may be a fixed point, a limit cycle, or irregular motion. By elastically coupling N airfoils, a simplified rotor model is obtained. The nonlinear dynamical response of the rotor is studied via time integration with particular attention to the emergence of localized vibrating solutions, which have been classified introducing a localization coefficient. Finally, the concept of basin stability is exploited to ascertain the likelihood of the system to converge to a certain localized state as a function of the airstream velocity. We found that homogeneous and slightly localized states are more likely to appear with respect to strongly localized states.
Organising professional support staff at higher education institutions: a multidimensional, continuous balancing act
Authors: Ryttberg Malin , Geschwind Lars
Published: January 2021

Centralisation is a recurrent theme when the organisational structure of contemporary higher education institutions is on the agenda. This may be in large part because of the unsolicited effects of decentralised organisational structures. The aim of this study is to explore how professional support staff at higher education institutions perceive the organisational structure of support and the rationales for this organising. An analytical framework based on the dichotomy of centralisation/decentralisation was applied in 18 interviews with professional support staff at one Dutch university and one Norwegian university. A common theme in the findings was the consciousness among the professional support staff that there is no one-size-fits-all solution for the organising of efficient and effective support. The issue of centralisation and standardisation was clearly on the agenda, but their focus was on the elements of a well-functioning support structure, not the specific organisational solution. The study also highlights the objection to the trend towards centralisation, and that some organisational changes may be too short sighted to be sustainable. From the perspective of the professional support staff, it can be concluded that organisational structure is a continuous balancing act based on dialogue between the academic and support staff.
Multimethod assessment of self-regulated learning in college students: different methods for different components?
Authors: Dörrenbächer-Ulrich Laura , Weißenfels Marie , Russer Lea , Perels Franziska
Published: January 2021

Although self-regulated learning (SRL) is seen as highly relevant for successful college learning, college students oftentimes show a lack in SRL abilities. Therefore, it seems necessary to foster SRL in this group of leaners. In order to evaluate such training and to foster SRL in an optimal way, a valid assessment of this competence and its development is necessary. As different methods for the assessment of SRL show benefits and points of criticism, the present study used a multimethod approach to investigate convergence between and across different measures as well as their predictive validity for achievement. SRL was conceptualized of cognitive, metacognitive, and motivational components. Seventy college students were assessed with two broad SRL-measures (questionnaire, strategy knowledge test) and two task-specific SRL measures (microanalyses, trace data) within a standardized laboratory setting. Moreover, GPA of college entrance diploma was gathered as an indicator of general achievement level. Results indicate moderate to high relations between the different components of SRL (cognition, metacognition, and motivation) within one assessment level and no relations between the different assessment methods within one component. With regard to achievement, we found that every component is predictive for achievement but only if measured with different assessment methods. The results are discussed with regard to their implications for future research and the use of different assessment methods for SRL.
Upland burning and grazing as strategies to offset climate-change effects on wetlands
Authors: McKenna Owen P. , Renton David A. , Mushet David M. , DeKeyser Edward S.
Published: January 2021

Wetland ecosystems perform a multitude of services valued by society and provide critical habitat for migratory birds and other wildlife. Despite their importance, wetlands have been lost to different local, regional, and global drivers. Remaining wetlands are extremely sensitive to changing temperature and precipitation regimes. Management of grassland areas in wetland catchments may be an effective strategy for counteracting potentially negative impacts of climate change on wetlands. Our objective was to estimate the effects of climate changes on wetland hydrology, and to explore strategies for increasing surface-water inputs to wetlands. We coupled a field study with process-based simulation modeling of wetland-water levels. We found that climate change could decrease the number of wetlands that hold ponded water during the waterfowl breeding season by 14% under a hot wet scenario or 29% under a hot dry scenario if no upland-management actions were taken. Upland burning reduced pond losses to 9% (hot wet) and 26% (hot dry). Upland grazing resulted in the smallest loss of ponded wetlands, 6% loss under the hot-and-wet scenario and 22% loss under the hot-and-dry scenario. Overall, water inputs could be increased by either burning or grazing of upland vegetation thereby reducing pond losses during the waterfowl breeding season. While field results suggest that both grazing and burning can reduce the vegetative structure that could lead to increases in runoff in grassland catchments, our model simulations indicated that additional actions may be needed for managers to minimize future meteorologically driven water losses.
Are topological explanations really free of mechanisms?
Authors: Zhang Xin
Published: January 2021

Topological explanations in biology have been largely assumed to be free of mechanisms. However, by examining two classic topological explanations in the philosophical literature, this article has identified mechanisms in the corrected and complete formulations of both explanations. This constitutes the major work of this article. The minor work of this article is to address a follow-up question: given that these two topological explanations contain mechanisms, would this significantly blur the widely assumed boundary between topological and mechanistic explanations? My answer to this question is negative and the argument I have developed is that although these two topological explanations contain mechanisms, these mechanisms are explanatorily irrelevant to the target properties, which is in stark contrast to the situation in mechanistic explanations.
CCN2 (Cellular Communication Network factor 2) in the bone marrow microenvironment, normal and malignant hematopoiesis
Authors: Leguit Roos J. , Raymakers Reinier A. P. , Hebeda Konnie M. , Goldschmeding Roel
Published: January 2021

CCN2, formerly termed Connective Tissue Growth Factor, is a protein belonging to the Cellular Communication Network (CCN)-family of secreted extracellular matrix-associated proteins. As a matricellular protein it is mainly considered to be active as a modifier of signaling activity of several different signaling pathways and as an orchestrator of their cross-talk. Furthermore, CCN2 and its fragments have been implicated in the regulation of a multitude of biological processes, including cell proliferation, differentiation, adhesion, migration, cell survival, apoptosis and the production of extracellular matrix products, as well as in more complex processes such as embryonic development, angiogenesis, chondrogenesis, osteogenesis, fibrosis, mechanotransduction and inflammation. Its function is complex and context dependent, depending on cell type, state of differentiation and microenvironmental context. CCN2 plays a role in many diseases, especially those associated with fibrosis, but has also been implicated in many different forms of cancer. In the bone marrow (BM), CCN2 is highly expressed in mesenchymal stem/stromal cells (MSCs). CCN2 is important for MSC function, supporting its proliferation, migration and differentiation. In addition, stromal CCN2 supports the maintenance and longtime survival of hematopoietic stem cells, and in the presence of interleukin 7, stimulates the differentiation of pro-B lymphocytes into pre-B lymphocytes. Overexpression of CCN2 is seen in the majority of B-acute lymphoblastic leukemias, especially in certain cytogenetic subgroups associated with poor outcome. In acute myeloid leukemia, CCN2 expression is increased in MSCs, which has been associated with leukemic engraftment in vivo. In this review, the complex function of CCN2 in the BM microenvironment and in normal as well as malignant hematopoiesis is discussed. In addition, an overview is given of data on the remaining CCN family members regarding normal and malignant hematopoiesis, having many similarities and some differences in their function.
Behavioral Effects of 4-CMC and 4-MeO-PVP in DBA/2J Mice After Acute and Intermittent Administration and Following Withdrawal from Intermittent 14-Day Treatment
Authors: Wojcieszak Jakub , Kuczyńska Katarzyna , Zawilska Jolanta B.
Published: January 2021

Synthetic cathinones appeared on the market in the 2000s as new psychoactive substances and gained significant prevalence among drug abusers. Cathinones produce psychostimulant and empathogenic effects by enhancing dopaminergic, noradrenergic, and serotoninergic neurotransmission in the brain, and those which potently and selectively enhance dopaminergic transmission are considered to have higher abuse potential. The present study examines the behavioral effects related to psychostimulant properties, abuse potential, and addiction in DBA/2J mice of two cathinones with different profile of action on monoamine system, 4-chloromethcathinone (4-CMC), and 4-methoxy-pyrrolidinopentiophenone (4-MeO-PVP). 4-CMC and 4-MeO-PVP increase spontaneous locomotor activity after acute treatment and produce behavioral sensitization after 7-day intermittent treatment, which is a common feature of drugs of abuse. 4-MeO-PVP, but not 4-CMC, produces conditioned place preference after 4 days, indicating its rewarding properties. Finally, the ability of 4-CMC and 4-MeO-PVP to induce withdrawal symptoms after discontinuation from 14-day treatment was assessed using a battery of tests for behavioral markers of depression in mice: a tail suspension test, a forced swim test, measuring despair, and a sucrose preference test, measuring anhedonia. None of the three tests revealed increased depressive symptoms. Moreover, neither spontaneous locomotor activity nor motor performance on a rotarod was impaired after 14-day treatment with the tested compounds. These results indicate that 14-day treatment of mice with 4-CMC or 4-MeO-PVP does not induce significant withdrawal symptoms after cessation, nor significant impairment of dopaminergic circuitry resulting in motor impairment. The current study shows that 4-CMC and 4-MeO-PVP produce abuse-related behavioral changes in mice, which are more pronounced after more dopamine-selective 4-MeO-PVP.
Gelatin-based composite hydrogels with biomimetic lubrication and sustained drug release
Authors: Zhang Kuan , Yang Jielai , Sun Yulong , Wang Yi , Liang Jing , Luo Jing , Cui Wenguo , Deng Lianfu , Xu Xiangyang , Wang Bo , Zhang Hongyu
Published: January 2021

The occurrence of osteoarthritis is closely related to progressive and irreversible destruction of the articular cartilage, which increases the friction significantly and causes further inflammation of the joint. Thus, a scaffold for articular cartilage defects should be developed via lubrication restoration and drug intervention. In this study, we successfully synthesized gelatin-based composite hydrogels, namely GelMA-PAM-PMPC, with the properties of biomimetic lubrication and sustained drug release by photopolymerization of methacrylic anhydride modified gelatin (GelMA), acrylamide (AM), and 2-methacryloyloxyethyl phosphorylcholine (MPC). Tribological test showed that the composite hydrogels remarkably enhanced lubrication due to the hydration lubrication mechanism, where a tenacious hydration shell was formed around the zwitterionic phosphocholine headgroups. In addition, drug release test indicated that the composite hydrogels efficiently encapsulated an anti-inflammatory drug (diclofenac sodium) and achieved sustained release. Furthermore, the in vitro test revealed that the composite hydrogels were biocompatible, and the mRNA expression of both anabolic and catabolic genes of the articular cartilage was suitably regulated. This indicated that the composite hydrogels could effectively protect chondrocytes from inflammatory cytokine-induced degeneration. In summary, the composite hydrogels that provide biomimetic hydration lubrication and sustained local drug release represent a promising scaffold for cartilage defects in the treatment of osteoarthritis.
Modeling the impact of climate change on the hydrology of Andasa watershed
Authors: Tarekegn Negusu , Abate Brook , Muluneh Alemayehu , Dile Yihun
Published: January 2021

This paper was aimed to study the impact of climate change on the hydrology of Andasa watershed for the period 2013–2099. The soil and water assessment tool (SWAT) was calibrated and validated, and thereby used to study the impact of climate change on the water balance. The future climate change scenarios were developed using future climate outputs from the Hadley Center Climate Model version 3 (HadCM3) A2 (high) and B2 (low) emission scenarios and Canadian Earth System Model version 2 (CanESM2) Representative concentration pathways (RCP) 4.5 and 8.5 scenarios. The large-scale maximum/minimum temperature and rainfall data were downscaled to fine-scale resolution using the Statistical Downscaling Model (SDSM). The mean monthly temperature projection of the four scenarios indicated an increase by a range of 0.4–8.5 °C while the mean monthly rainfall showed both a decrease of up to 97% and an increase of up to 109%. The long-term mean of all the scenarios indicated an increasing temperature and decreasing rainfall trends. Simulations showed that climate change may cause substantial impacts in the hydrology of the watershed by increasing the potential evapotranspiration (PET) by 4.4–17.3% and decreasing streamflow and soil water by 48.8–95.6% and 12.7–76.8%, respectively. The findings suggested that climate change may cause moisture-constrained environments in the watershed, which may impact agricultural activities in the watershed. Appropriate agricultural water management interventions should be implemented to mitigate and adapt to the plausible impacts of climate change by conserving soil moisture and reducing evapotranspiration.
Morphological and biochemical responses of Sorghum bicolor (L.) Moench under drought stress
Authors: Sarshad Assad , Talei Daryush , Torabi Masoud , Rafiei Farnaz , Nejatkhah Parisa
Published: January 2021

Sorghum is an important forage crop, and both quantity and quality of this crop are affected by drought stress. Accordingly, in order to investigate the effect of drought stress on quantity and quality of morpho-physiological traits, a split-plot experiment was conducted based on randomized complete block design with four replicates in Isfahan, Iran, during 2017 and 2018 crop seasons. Treatments were irrigation regimes with four levels (control, preventing irrigation at pollination, seed milky, and seed doughy stages) and three varieties of sorghum (Sepideh, Kimia, and Payam). The results showed that drought stress negatively influenced morphological and yield-related traits of sorghum, while its effect was positive on some quality-related traits such as total soluble carbohydrate, crude protein, and proline contents. According to the results, drought stress based on prevention of irrigation at doughy stage (representing moderate drought stress) caused inconsiderable reduction in sorghum yield. In addition, drought stress has effect on relationships between morpho-physiological traits in sorghum. Considering morphological and yield-related traits together with susceptibility (stress susceptibility index) and tolerance (geometric mean product) indices indicated that Payam variety is more proper to be used in both drought stress and non-stress conditions. Furthermore, both Kimia and Payam varieties were shown to be suitable varieties based on quality-related traits, but because of having low NDF Payam variety might be more suitable.
Neuro-fuzzy based predictive model for cutting force in CNC turning process of Al–Si–Cu cast alloy using modifier elements
Authors: Marani Mohsen , Zeinali Mohammadjavad , Farahany Saeed , Mechefske Chris K.
Published: January 2021

This study investigated the predicted cutting force model of a turning operation for Al–Si–Cu cast alloy modified with modifiers based on adaptive neuro-fuzzy inference system (ANFIS) approach. Feed rate, cutting speed and Silicon spacing were considered as the input parameters. A series of turning experiments were conducted at various feed rates and cutting speeds. The prediction result showed that the ANFIS model successfully predicted the cutting force value in terms of cutting speed, feed rate and Si spacing. A mathematical model was proposed to describe the cutting force changes during the machining of Al–Si–Cu cast alloy. Moreover, the addition of Bismuth into the base alloy decreased the cutting force compared to other refinement elements.
Understanding the characteristics of rapid intensity changes of Tropical Cyclones over North Indian Ocean
Authors: Nadimpalli Raghu , Mohanty Shyama , Pathak Nishant , Osuri Krishna K. , Mohanty U. C. , Chatterjee Somoshree
Published: January 2021

North Indian Ocean (NIO), which comprises of Bay of Bengal (BoB) and Arabian Sea (AS) basins, is one of the highly potential regions for Tropical Cyclones (TCs) in the world. Significant improvements have been achieved in the prediction of the movement of TCs, since the last decade. However, the prediction of sudden intensity changes becomes a challenging task for the research and operational meteorologists. Hence, the present study focuses on finding the climatological characteristics of such intensity changes over NIO regions. Rapid Intensification (RI) is defined as the 24-h maximum sustained surface wind speed rate equal to 30 knots (15.4 ms−1). The results suggest that the TCs formed over the NIO basin are both seasonal and basin sensitive. Since 2000, a significant trend is observed in RI TCs over the basin. At least one among three cyclones getting intensified is of RI category. More number of RI cases have been identified in the BoB basin than the AS. The post-monsoon season holds more RI and rapid decay cases, with 63% and 90% contribution. Most of the TCs are attaining RI onset in their initial stage. Further, India is receiving more landfalling RI TCs, followed by Bangladesh and Oman. The east coast of India, Tamil Nadu, and Andhra Pradesh are the most vulnerable states to these RI TCs. The cyclogenesis locations associated with RI cases hold higher moisture, and sea surface temperature as compared to the Non-RI cases.
Detailed vibrational analysis of unbalanced morning glory spillways using coupled finite volume-finite element method
Authors: Mirabi Mohammad H. , Akbari Hassan , Alembagheri Mohammad
Published: January 2021

In this research, the structural behavior of a morning glory spillway has been evaluated when there is an unbalanced construction in the spillway crest. The unbalanced construction is defined as the ratio of vertical unbalance in construction to the diameter of the spillway crest. The spillway structure has been modeled using finite element method and the reservoir fluid has been simulated using finite volume method. The behavior of morning glory spillways with unbalanced crests has been investigated in two scenarios: (a) the crest without any anti-vortex structure, and (b) the crest with anti-vortex structures. Both scenarios have been simulated using dynamic linear analysis method. In addition, in each scenario, three amounts of unbalanced constructions of 0.017, 0.035 and 0.052 have been considered. The analysis results have been compared with the structural response of a symmetric spillway without unbalanced construction. Based on the results, the most critical condition occurs during the water flow over the unbalanced spillway with no anti-vortex structure. On the other hand, the presence of anti-vortex piers causes asymmetric flow on the spillway crest and subsequently asymmetric flow pressure at one side of the piers.
Bioconvection casson nanofluid flow together with Darcy-Forchheimer due to a rotating disk with thermal radiation and arrhenius activation energy
Authors: Saeed Anwar , Gul Taza
Published: January 2021

In this research article, we examined the Darcy-Forchheimer 3D in bioconvection Casson nanofluid flow in light of a whirling disk with Arrhenius Activation Energy and thermal Radiation. The governing equations are converted to the similarity equations and solved afterward by utilizing the Homotopy Analysis Method on behalf of several controlling parameters. The findings from this study show, that the radial velocity and tangential component of velocity decreasing for increasing values of the Inertia coefficient and the Porosity parameter. Velocity profiles enlarge with the enlargement of $$Gr$$

Gr

for nanofluids. Radial velocity diminishes with expanding Reynolds numbers $${\text{Re}}_{r}$$

Re
r

and magnetic field parameters. The tangential component of velocity $$g\left( \xi \right)$$

g

ξ

increases with diminishing Reynolds numbers $${\text{Re}}_{r}$$

Re
r

and reduces with expanding magnetic field factors. For increasing values of Prandtl number temperature profile is increased. Heat rises with radiation parameter, thermophoresis and Brownian movement parameters. Also, nanoparticles concentration reduces on expanding Brownian motion parameter and Schmidt parameter.
Assessment of bacterial contamination of Mytilus galloprovincialis, Cardium edule and water quality in Bouregreg estuary (Morocco, Atlantic Ocean)
Authors: Salama Youssef , Salama Othmane , El Amraoui Mohammed , Chennaoui Mohammed
Published: January 2021

The Moroccan marine environment is threatened by several types of pollution. Indeed, the littoral zone knew an urban, industrial and agricultural development without precedent; moreover, coastal waters have served as discharges for almost all activities linked to this development. The aim of this study is to determine the biological, physicochemical and bacteriological quality of waters and bivalve shells in the Bouregreg estuary. Sampling was carried out at four stations (S1, S2, S3 and S4) located downstream to upstream of the estuary. Thus, we analysed the degree of contamination by total coliform, faecal coliform and faecal streptococci in the water and in the flesh ofMytilus galloprovincialisandCardium eduleand determined the physicochemical parameters of seawater samples, which included temperature, dissolved oxygen, electrical conductivity, pH, total hardness, biological oxygen demand for five days (BOD5), complete alkalimetric title, NO2−, NO3−, NH4+, Fe2+, K+, SO42−, HCO3−, Cl−, Na+, Mg2+and Ca2+. The S1, S2 and S3 stations were shown to have more or less homogeneous physicochemical properties. The evolution of faecal bacteriological contamination of water and bivalves has shown that faecal pollution of the environment varies according to the stations and according to the seasons. The degree of contamination is high in autumn and winter and comes from wastewater and runoff discharges which, by leaching agricultural land, bring a large number of microorganisms to the environment. This influences the quality of the aquatic fauna, in particular, the infestation of lamellibranch molluscs such as inMytilus galloprovincialisandCardium edule. We have noted that the contamination of mussels by these types of microorganisms follows, more or less, that of the biotope. It should also be noted that in summer, the faecal contamination of the environment increases with the arrival of summer visitors.
Assessment of carbonaceous fractions in ambient aerosols at high altitude and lowland urban locations of Kumaon Province, Indian Himalaya
Authors: Kumar Amit , Singh Sachchidanand , Kumar Niraj , Singh Narendra , Kumar Krishan , Chourasiya Sapna
Published: January 2021

The present study investigates the characteristics of carbonaceous species like organic carbon (OC) and elemental carbon (EC) in ambient total suspended particulates (TSP) at Bhimtal (high altitude urban, 1413 m asl) and Pantnagar (lowland urban, 224 m asl) sites of Kumaon province in Uttarakhand, Indian Himalayan region during winter and summer 2017–2018. Ambient TSP samples were taken on quartz filters with high volume sampler followed by OC and EC quantification using IMPROVE_thermal optical reflectance protocol. Results showed that distinct seasonal differences in carbonaceous species levels were observed at both sites, while day- and night-time concentrations did not show notable variations. Further, total carbonaceous aerosols (TCA) at Pantnagar were approximately 3.0 and 1.3 times higher than Bhimtal for winter and summer, respectively, where estimated TCA accounted for ~ 30% to total TSP at both sites. Among quantified eight carbon fractions, OC2 and OC3 at Bhimtal while EC1 and EC2 at Pantnagar were the most abundant components. The char-EC and soot-EC concentrations showed a similar seasonal pattern where char contributed significantly as 89–90% to total EC at both sites. The observed OC/EC ratios suggested the formation of secondary organic carbon and char-EC/soot-EC ratios implied biomass burning as major sources for carbonaceous aerosols. Pearson correlation analysis indicated that char-EC showed significant higher correlations with OC and EC than soot-EC which infers different formation mechanisms of char and soot. Most of the carbonaceous parameters exhibited contrasting positive and negative correlations with the boundary layer height, temperature, and solar radiation at Bhimtal and Pantnagar, respectively.
Fuzzified Coulomb’s and Franklin’s laws behaved optimization for economic dispatch in multi-area multi-fuel power system
Authors: Sakthivel V. Ponnuvel , Sathya P. Duraisamy
Published: January 2021

Multi-Area Multi-Fuel Economic Dispatch (MAMFED) aims to allocate the best generation schedule in each area and to offer the best power transfers between different areas by minimizing the objective functions among the available fuel alternatives for each unit while satisfying various constraints in power systems. In this paper, Fuzzified Coulomb’s and Franklin’s Laws Behaved Optimization (FCFLBO) approach is proposed to solve the MAMFED problem. Coulomb’s and Franklin’s Laws Behaved Optimization (CFLBO) approach is developed from Coulomb’s and Franklin’s theories, which encompass fascination/aversion, ionization, and contact stages. The suggested approach considers the line losses, valve point loading impacts, multi-fuel alternatives, and tie-line limits of the power system. Because of the contradicting nature of fuel cost and pollutant emission objectives, weighted sum approach and price penalty factor are used to transfer the bi-objective function into single objective function. Furthermore, a fuzzy decision strategy is introduced to find one of the Pareto optimal fronts as the best comprised solution. The feasibility of the FCFLBO algorithm is tested on a three-area test system for both the single-area multi-fuel economic dispatch and MAMFED problems. The results of FCFLBO algorithm are compared with those of the krill herd algorithm, exchange market algorithm and other heuristic approaches surfaced in the literature. To show the effectiveness of FCFLBO algorithm, multi-objective performance indicators such as generational distance, spacing metric and ratio of non-dominated individuals are evaluated. The results divulge that the FCFLBO is a promising approach to solve the MAMFED problem as it furnishes better compromised solution in comparison with the other heuristic approaches.
Swept Langmuir probe investigation of a time varying DC discharge
Authors: Qayyum A. , Naseer M. Usman , Deeba F. , Ahmad S. , Shah S. I. W. , Imran Mubashair , Hussain S. , Zakaullah M.
Published: January 2021

The paper reports on the development and application of a swept Langmuir probe to characterize plasma between two disc-like electrodes. A battery was added to a probe circuit to offset against the cathode fall voltage, and to make the sweep voltage effective at the probe tip. This arrangement allowed the collection of the electron and ion parts of the probe current and the subsequent construction of time-resolved current–voltage IP(V) characteristics with a time resolution of about one millisecond. The probe collected electron current in the lower voltage region of the discharge waveform where it surmounted the cathode fall voltage, whereas the ion current was collected continuously due to an accelerating field for the ions. The results highlighted how the cathode fall voltage limits the collection of the electron and ion parts of the probe current and how to handle the problem with a series battery in the probe circuit. In addition to the swept single-probe, a triple-probe was used simultaneously to compare and validate the results.
Evaluation of the permeability of high strength concrete using metakaolin and wood ash as partial replacement for cement
Authors: Kannan V. , Raja Priya P.
Published: January 2021

The present study is aimed to develop a high strength concrete by using mineral admixtures of wood ash (WA), metakaolin (MK), and chemical admixture. In order to check the compatibility, physical and chemical properties of the materials are studied. The specific gravity, bulk density and fineness of the ordinary Portland cement, wood ash and metakaolin have been studied. When compare to other materials, metakaolin has a more fineness and it implies the more reactivity than the wood ash. Similarly, the physical properties of the fine aggregate and coarse aggregates are also studies. And compressive strength, water absorption test, rapid chloride penetration test is also conducted. From the test report, it can be noted that the maximum compressive strength is achieved 83 N/mm2 in 10% WA + 20% MK blended concrete. The lowest water absorption and chloride permeability were obtained as 2.5% and 348 C respectively in 10% WA + 20% MK blended concrete. At the end of the experimental works, all obtained results were correlated with each other. The water absorption is well correlated with compressive strength (R2 = 84.9%) and charge passed (R2 = 91.5%). Finally, the cost analysis was carried out to understand the cost benefits of using the wood ash and metakaolin in high strength concrete.
Sustainable water management in the Angkor Temple Complex, Cambodia
Authors: Chim Kosal , Tunnicliffe Jon , Shamseldin Asaad , Sarun Sambath
Published: January 2021

The headwater catchment of the Siem Reap River has supplied the Angkor Temple Complex and surrounding communities since the twelfth century. The Angkor Temple Complex area consists of historical moats and barays (reservoirs) which are currently used to store the water from the Siem Reap River to maintain temple foundation, irrigate cultivation areas and provide floodwater storage. The Angkor Wat Temple, which is located in the complex, was constructed on a sandy alluvial substrate and needs a stable supply of water to avert land subsidence and destabilization of the temple foundation. In light of changing climate, land use and land cover (LULC) trends, it is crucial to examine the wide-ranging implications of reduced water supply for the Angkor Temple Complex. Using the Soil and Water Assessment Tool, this study seeks to assess the conditions necessary to provide sustainable streamflow to the Angkor Temple Complex. We modelled 30 scenarios of co-varied LULC and precipitation regime under a changing climate. The results show that under most LULC scenarios, sufficient water resources can be harvested to supply the complex—however—any further loss of forest cover is likely to impact groundwater conditions, flood management and dry season shortages. Conversely, the water supply to the complex is shown to be sensitive under the range of climate scenarios explored; a reduction of more than 10–20% in mean annual precipitation was enough to put the water supply under stress for the current and future conditions of the complex.
Experimental study of the addition of oil palm mesocarp fiber on the physical and mechanical properties of fiber cement mortar composites
Authors: Bopda Fokam Christian , Toumi Eric , Kenmeugne Bienvenu , Wiryikfu Nfor Clins , Mevaa Lucien
Published: January 2021

Composite materials based on natural fibers are increasing in demand in various sectors of industry because of their interesting specific properties. This work is a contribution to the valorization, of plant fibers from agricultural plantations in Cameroon, in fiber cement mortar (FCM). This paper studies the influence of the addition of oil palm mesocarp fiber (OPMF) on the physical (water absorption, density and compactness) and mechanical (compressive strength and flexural strength) properties of cement mortars. The fibers used in this paper are extracted from oil palm mesocarp (palm kernel pulp) by a mechanical and manual process. Cement mortar specimens were then made with different proportions of fibers: 0% (reference mortar), 1%, 2%, 3% and 3.5% fibers. Physical and mechanical tests are then carried out on our specimens. Regardless of the duration of immersion in water, the results show that the water absorption rate increases with a greater amount of fiber in the FCM specimens. On the other hand, an inverse effect is observed on density, which decreases from 2277.5 (samples with 0% fiber) to 942.1 kg/m3 (samples with 3.5% fiber) for apparent density and from 2641.2 to 1945.7 kg/m3 for absolute density. On the mechanical properties, there is a steady decrease in compressive strength from 42.47 (for the reference mortar at 0% fiber) to 31.1 MPa (for the sample at 3.5% fiber). In bending, there is first an increase and then a decrease in strength with the amount of fibers. The maximum flexural strength is obtained for a 2% fiber composition. The FCM has a better strength/density ratio. Finally, the addition of OPMF, in small proportion in the cement mortar, allows a lightening of the structure, but induces a small decrease in mechanical resistance. Our FCM can be used in the manufacture of cinderblocks or as internal wall roughcoating mortar.
Cross-layer unequal error protection using 64-HQAM and RCPT codes for robust image communication
Authors: Mobin Anam , Khan Ekram , Beg Mirza Salim
Published: January 2021

In unequal error protection (UEP) schemes, the bits are protected according to their significance in terms of distortion reduction capability during the reconstruction process. The conventional UEP schemes are primarily designed either using forward error correction at application layer of network architecture, or hierarchical modulation at the physical layer. In this paper, an optimized cross-layer UEP scheme for set partitioning in hierarchical trees coded images is investigated. The proposed scheme uses rate compatible punctured turbo codes at application layer and two-layered 64-hierarchical QAM (64-HQAM) at physical layer. Simulation results show that proposed cross-layer UEP performs slightly better than application layer’s optimized turbo coding for additive white Gaussian noise channel but performs significantly better in flat Rayleigh fading channel, specifically under poor channel conditions. The proposed scheme is highly bandwidth efficient having the robustness performance close to that of the scheme using hierarchical 4-PAM (H 4-PAM). Complexity analysis of the proposed solution has been carried out.