bluuebunny/crossref_metadata_2025 huggingface dataset:
Land use intensification affects the relative importance of climate variation and active land degradation: Convergence of six regions around the world
Authors: Sanjuán María E. , Martínez‐Valderrama Jaime , Ruiz Alberto , del Barrio Gabriel
Published: May 2022

We explored the relative importance of climate oscillations and human‐driven disturbances on the change in vegetation biomass in agroecosystems, and whether it is associated with land use. Our main contribution is a quantitative treatment of these factors in equivalent terms, i.e. not assuming any of them to be principal. The study was carried out in the drylands of the Iberian Peninsula, NW Maghreb, Palestinian West Bank, Mozambique, China and NE Brazil, using satellite time‐series and the corresponding climate fields, at ten‐year observation periods with spatial and temporal resolutions of 1000 m (250 m in Palestine) and one year, respectively. For each region, we separated the relative weights of climate and time by fitting multiple‐stepwise regressions to a vegetation index as the dependent variable, and annual aridity (Aridity) and year number (Time) as predictors. The relative strength of the resulting standard partial regression coefficients was then compared by the Wilcoxon signed ranks test, and their combined associations with land uses were determined using Chi‐square tests. Some points of convergence are as follows: (1) The relative weights of Aridity and Time depend on particular regional conditions and can be determined. (2) Such weights are associated with land use intensification, such that if vegetation increases over Time, Aridity increases its relative importance with intensification; if vegetation is degrading, Aridity is always more important than Time. (3) Aridity is an indicator of vulnerability to climate warming. Resilience can be improved by reducing land use intensification. 4. Vulnerability may worsen under constant climate if agriculture is intensified. These patterns enhance an integrated understanding of Sustainable Development Goals Indicator 15.3.1, particularly its land cover and productivity trend components.
Design for Recycling Strategies Based on the Life Cycle Assessment and End of Life Options of Plastics in a Circular Economy
Authors: Venkatachalam Venkateshwaran , Pohler Merlin , Spierling Sebastian , Nickel Louisa , Barner Leonie , Endres Hans‐Josef
Published: May 2022

The plastic economy, despite offering unique properties in fulfilling the functions of products in different industrial sectors over decades, has so far been mainly linear, that is, “take‐make and dispose” with only a small fraction of plastics being recycled worldwide. With ever‐increasing circular economy initiatives and the urge to conserve resources and prevent plastic pollution from affecting ecosystems, more emphasis on the resource recovery of plastic products after its use has been made over the last few years. It is necessary for manufacturers to understand the value chain as early as the design phase while manufacturing and distributing plastic products across the world. The current study provides an overview of the status quo of plastic waste management and analyzes the Life Cycle Assessment (LCA) studies of different End‐of‐Life (EoL) options for plastics. Based on the LCA studies, a preliminary, country‐specific Circular Footprint (CF) is calculated and Design for Recycling (DfR) strategies are identified. Results show that the environmental impacts of different EoL options differ significantly for different plastics. The CF highlights the lack of data regarding the composition and recovery of plastics in different countries thus showing the necessity to consider the whole lifecycle when quantifying the environmental impacts of plastics.
Dehydrofluorination and One‐Pot Hydrothermal Process for Polyvinylidene fluoride/Polytetrafluoroethylene@TiO2 Membranes with Durable Superhydrophobicity toward Repeatable Separating and Photodegrading Oily Dyes in Water‐in‐Oil Emulsions
Authors: Deng Linghan , Tan Yong , Tian Xingyu , Huang Hongyan , Xie Quanpei , Sun Chaohai , Qin Chuanxiang , Cheng Si
Published: May 2022

The photocatalytic and inherently hydrophilic characteristic of titanium dioxide (TiO2) make it very suitable for separating oil‐in‐water emulsion and aqueous pollutants removal. However, the removal of the oily dyes in water‐in‐oil emulsion usually needs superhydrophobic/superoleophilic membranes. Although surface modification of TiO2 with fluorinated organic compounds can bring hydrophobicity, the hydrophobic surface would change back to a hydrophilic surface again after light illumination as fluorinated organic molecules are easily photodegraded too. To date, very few reports have successfully fabricated TiO2 photocatalysts keeping long‐term superhydrophobicity after repeatable photodegradation. Herein, an approach to fabricate polyvinylidene fluoride (PVDF)/polytetrafluoroethylene (PTFE) @TiO2 nanofibrous membranes through dehydrofluorination and one‐pot hydrothermal process, which possess stable superhydrophobicity in various harsh environments, is reported. For the first time, PTFE is bonded with PVDF through dehydrofluorination which induces crosslinking between PTFE and PVDF chains. Owing to the existence of PTFE, extensive hydrophobic TiO2 can be in situ grown on the rough surface of PVDF/PTFE nanofibers through one‐pot hydrothermal process. These features ensure that the membranes possess durable and high‐efficient water‐in‐oil emulsion separation and photodegradation performance. The photodegradation efficiency of the PVDF/PTFE@TiO2 membranes for oil‐soluble dyes remains above 95% even after ten cycles.
Investing in entrepreneurs: The case of franchising
Authors: Michael Steven C.
Published: May 2022

Whether meant to improve public policy, private lending, or personal choices by individuals, investing in successful entrepreneurs is essential. Successful entrepreneurs typically have high human capital. Investment in entrepreneurs who have lower human capital involves more risk. Research has shown that one type of entrepreneur, franchisees, typically possess lower human capital than entrepreneurs generally. Examining a unique data set of loans by the US government to small businesses, we compare all recipients of these loans, controlling for other relevant lending, economic, and social factors. We find that franchisees have higher default rates and higher lending losses than independents.
Can an increase in the minimum wage standard force enterprises to innovate? Evidence from China
Authors: Li Zheng , Liu Fengshuo , Mi Shuai
Published: May 2022

This paper examines the impact of an increase in the minimum wage standard on enterprise innovation and its mechanism. Based on the matching data between China's A‐share listed enterprises and the city minimum wage standard from 2003 to 2018, we find that an increase in the minimum wage standard promotes enterprise innovation, and this impact is sustainable. Mechanism analysis shows that an increase in the minimum wage standard enlarges R&D investments and personnel to promote enterprise innovation. In addition, we find that an increase in the minimum wage standard has a stronger effect in promoting the innovation of large, labour‐intensive, high‐innovation or non‐state‐owned enterprises than the others.
Exploring a new discrete delayed Mittag–Leffler matrix function to investigate finite‐time stability of Riemann–Liouville fractional‐order delay difference systems
Authors: Du Feifei , Lu Jun‐Guo
Published: May 2022

In this paper, firstly, a new discrete delayed Mittag–Leffler matrix function is introduced, which generalizes the existing discrete delayed exponential matrix function. Secondly, based on it, the explicit formula of the solution of homogeneous Riemann–Liouville (RL) fractional‐order delay difference system is obtained. Thirdly, the explicit formulas of the solutions of nonhomogeneous RL fractional‐order delay difference systems are also derived in terms of the superposition principle and the new discrete delayed Mittag–Leffler matrix function. Furthermore, a finite‐time stability (FTS) criterion of nonhomogeneous RL fractional‐order delay difference system is given using the properties of the new discrete delayed Mittag–Leffler matrix function. Finally, three examples are presented to demonstrate the effectiveness of the proposed theorems.
Bifurcation analysis of a predator–prey model with Beddington–DeAngelis functional response and predator competition
Authors: Zhang Yuyue , Huang Jicai
Published: May 2022

In this paper, we consider a predator–prey model with Beddington–DeAngelis functional response and predator competition, which is a five‐parameter family of planar vector field. It is shown that the model can undergo a sequence of bifurcations including focus type degenerate Bogdanov–Takens bifurcation of codimension 3 and Hopf bifurcation of codimension at least 2 as the parameters vary. Our theoretical results indicate that predator competition can cause richer dynamics such as two limit cycles enclosing one or three hyperbolic positive equilibria and three kinds of homoclinic orbits (homoclinic to hyperbolic saddle, saddle‐node, or neutral saddle). Moreover, there exists a threshold value
for predator capturing rate
, below or equal to which the predators always tend to extinction, above which the predators and preys will coexist in the form of multiple steady states or periodic oscillations for all positive initial populations. Numerical simulations are presented to illustrate the theoretical results.
Intra‐arc binary collimation with dynamic axes trajectory optimization for the SRS treatment of multiple metastases with multiple prescriptions
Authors: Lee Eva , MacDonald R. Lee , Thomas Christopher G. , Syme Alasdair
Published: May 2022

Purpose

This work generates multi‐metastases cranial stereotactic radiosurgery/radiotherapy (SRS/SRT) plans using a novel treatment planning technique in which dynamic couch, collimator, and gantry trajectories are used with periodic binary target collimation. The performance of this planning technique is evaluated against conventional volumetric arc therapy (VMAT) planning in terms of various dose and plan quality metrics.

Methods

A 3D cost space (referred to herein as the combined optimization of dynamic axes or CODA cube) was calculated based on an overlap between targets and organs‐at‐risk (OARs) and uncollimated areas between targets (island blocking) for all combinations of couch, gantry, and collimator angles. Gradient descent through the cube was applied to determine dynamic trajectories. At each control point (CP), each target can either be conformally treated or blocked by the multi‐leaf collimator (referred to as intra‐arc binary collimation, iABC). Simulated annealing was used to optimize the collimation patterns throughout the arcs as well as the monitor units (MUs) delivered at each CP. Seven previously treated VMAT plans were selected for comparison against the CODA–iABC planning technique. Two CODA–iABC plans were developed: a single gantry arc plan and a plan with one gantry arc and two couch arcs. Plan quality comparison metrics included maximum and mean dose to OARs (brainstem, chiasm, optic nerves, eyes, and lenses), the volume of normal brain receiving 12 Gy (V12Gy), total MUs, target conformity, and dose‐gradient index.

Results

Treatment plans generated with 1‐arc CODA–iABC plans delivered an average of 21% and 30% higher maximum and mean doses to brainstem, respectively, when compared to VMAT plans. Treatment plans generated with 3‐arc CODA–iABC used an average of 24% fewer MUs and resulted in an average reduction of 48% maximum dose and 50% mean dose to the OARs, when compared to VMAT. Target conformity values were worse in both CODA–iABC plans than VMAT by an average of 35% and 15%, respectively. There are no significant differences in V12Gy for all three planning techniques; however, 3‐arc CODA–iABC is more effective at reducing dose to normal brain in the low‐dose region (<12 Gy).

Conclusion

CODA–iABC is a novel planning technique that has been developed to automatically generate patient‐specific multi‐axis trajectories for multiple metastases cranial SRS/SRT. This work has demonstrated the feasibility of planning with this novel method. The 1‐arc CODA–iABC planning technique is slightly dosimetric inferior to VMAT. With an increased sampling of a three‐dimensional CODA cube by using a 3‐arc CODA–iABC technique, there was improved total dose sparing to all the OARs and increased MU efficiency, but with a cost in target conformity, when compared to VMAT.
Alaskan Yelloweye Rockfish Fecundity Revealed through an Automated Egg Count and Digital Imagery Method
Authors: Arthur Donald E. , Falke Jeffrey A. , Blain-Roth Brittany J. , Sutton Trent M.
Published: May 2022

Spawning stock biomass (SSB) is often used as an index for reproductive potential (RP) in fisheries stock assessments. This method assumes that mature female biomass is proportional to total egg production and implies that (1) the fecundity–length relationship follows a cubic function or (2) relative fecundity is constant. For many marine fishes, adequate fecundity estimates to evaluate these relationships are lacking. This study estimated fecundity and fecundity relationships for Yelloweye Rockfish Sebastes ruberrimus and evaluated an automated method of counting eggs and larvae. We collected Yelloweye Rockfish ovaries (N = 90) from the northern Gulf of Alaska, including Prince William Sound, Alaska, during 2018–2019 and used the gravimetric method and image analysis software to count eggs from digital camera images. To evaluate the speed, accuracy, and precision of the automated counting procedure, one-third of the gravimetric samples were also manually counted. Image analysis software was approximately four times faster but equally accurate and precise for fecundity estimates relative to manual counts. Fecundity ranged from 53,249 to 3.052 × 106 eggs (mean ± SD = 896,762 ± 699,504 eggs), and relative fecundity increased with female FL and ranged from 68 to 435 eggs/g of body weight (mean ± SD = 226 ± 87 eggs/g). The use of SSB for Yelloweye Rockfish stock assessment could underestimate the contribution to egg production by larger (>5.6-kg) females, overestimate the contribution by smaller females, and lead to biased biological reference points. This study provides critical information to more realistically model RP and improve stock assessment inputs for the development of harvest control rules for Yelloweye Rockfish. Additionally, the use of image analysis software to count eggs in digital images proved to be an effective fecundity estimation method that could be applied to other highly fecund fish species for which the time demand of manual counting methods would be prohibitive.
Topology optimization for realizing tailored self‐collimation in phononic crystals
Authors: Jia Zhiyuan , Luo Yangjun , Takezawa Akihiro , Zhang Xiaopeng
Published: May 2022

Self‐collimation is a phenomenon that the waves propagate through a narrow channel in phononic crystals (PnCs) without diffusion. Although different self‐collimation PnCs configurations have been proposed with heuristic methods, it is still challenging to achieve a frequency‐specified self‐collimation. We propose a systematic topology optimization method to find the material distribution in PnCs for realizing a frequency‐specified self‐collimation within a wider incident wave angle range. To achieve the self‐collimation effect, the weighted slope index of equi‐frequency contours (EFCs) that effectively measures whether the wave propagation has a self‐collimation effect is introduced as the objective function of the optimization model. The material‐field series expansion (MFSE) technique is used to describe the complicated topologies of the unit cell with a low number of design variables. Then, the Kriging‐based optimization algorithm with a self‐adaptive strategy is adopted for solving the optimization problem. Numerical examples show that the optimized unit cell designs have flat EFCs within larger incident wave angle ranges and also demonstrate that the expected nondiffraction propagation characteristics can be achieved through optimization.
AWWA's Water Quality Laboratory Committee Provides Resources for Operators
Authors: Adams Hunter , Holloway Nicole
Published: May 2022

You can take the plant operator out of the laboratory, but you can't completely remove the need for the laboratory from the operator. Plant operations are fundamentally tied to the laboratory. One of the goals of the AWWA Water Quality Laboratory Committee is to disseminate information that can be used by plant operators.
Operators Need to Know Basics of Distribution System Water Quality
Authors: Adams Hunter , Ash Steve , Ikehata Keisuke , Furatian Laith , Southard Mark
Published: May 2022

Understanding how water quality is affected in the distribution system is key to ensuring drinking water quality.
Characterization of novel extracellular polymeric substances produced by Bacillus velezensis P1 for potential biotechnological applications
Authors: Binmad Sasithorn , Numnuam Apon , Kaewtatip Kaewta , Kantachote Duangporn , Tantirungkij Manee
Published: May 2022

Bacillus velezensis (B. velezensis) P1 released huge amount of exopolymeric substances (EPS), and its EPS was extracted and characterized. The extracted EPS strongly inhibited (88%–91%) the growth of two serious rice fungal pathogens. The main component of the EPS was protein (44%). Fourier transform infrared spectra of the EPS revealed a complex structure that contained sufficient negatively charged functional groups for the zeta potential of the compound to be highly negative (−33.83 mV). Scanning electron microscope images revealed plate‐like particles with smooth, clean surfaces. The EPS showed high degrees of whiteness (L* = 94.56) and crystallinity (87%), and was thermally stable up to 500°C. Flocculation activity in a kaolin dispersion was optimal at an EPS concentration of 12 mg L−1. The EPS preferred an alkaline condition, with the highest flocculation activity (76%) observed at pH 10. The EPS produced by B. velezensis P1 could be a potential material for applying in agriculture and industry.
Discordant cfDNA‐NIPT result unraveling a trisomy 12 chronic lymphocytic leukemia in a 37 years old pregnant woman
Authors: Di Giosaffatte Niccolò , Bottillo Irene , Laino Luigi , Iaquinta Giovanni , Ferraris Alessandro , Garzia Mariagrazia , Bargiacchi Simone , Mulargia Claudia , Angelitti Maria Rosaria , Palumbo Fabiana , Grammatico Barbara , Bartolelli Cinzia , Salerno Maria Giovanna , Rigacci Luigi , Grammatico Paola
Published: May 2022

Key points

What's already known about this topic?

Discordant NIPT results can rarely unravel maternal malignancies, especially when multiple chromosomal imbalances are reported. Both solid and hematological neoplasms have been described.

What does this study add?

This is the first case of a discordant NIPT result due to Chronic Lymphocytic Leukemia associated with trisomy of the chromosome 12. Putative maternal malignancy should be considered and investigated through sensitive techniques even in presence of a single chromosomal anomaly. This must be considered especially when the imbalance is known to recur in hematological neoplasms.
Lessons learnt from prenatal exome sequencing
Authors: Chandler Natalie J. , Scotchman Elizabeth , Mellis Rhiannon , Ramachandran Vijaya , Roberts Rowenna , Chitty Lyn S.
Published: May 2022

Background

Prenatal exome sequencing (ES) for monogenic disorders in fetuses with structural anomalies increases diagnostic yield. In England there is a national trio ES service delivered from two laboratories. To minimise incidental findings and reduce the number of variants investigated, analysis uses a panel of 1205 genes where pathogenic variants may cause abnormalities presenting prenatally. Here we review our laboratory's early experience developing and delivering ES to identify challenges in interpretation and reporting and inform service development.

Methods

A retrospective laboratory records review from 01.04.2020 to 31.05.2021.

Results

Twenty‐four of 116 completed cases were identified as challenging including 13 resulting in difficulties in analysis and reporting, nine where trio inheritance filtering would have missed the diagnosis, and two with no prenatal diagnosis; one due to inadequate pipeline sensitivity, the other because the gene was not on the panel. Two cases with copy number variants identified were not detectable by microarray.

Conclusions

Variant interpretation requires close communication between referring clinicians, with occasional additional examination of the fetus or parents and communication of evolving phenotypes. Inheritance filtering misses ∼5% of diagnoses. Panel analysis reduces but does not exclude incidental findings. Regular review of published literature is required to identify new reports that may aid classification.
Alternative analytic and matching approaches for the prevalent new‐user design: A simulation study
Authors: Webster‐Clark Michael , Mavros Panagiotis , Garry Elizabeth M. , Stürmer Til , Shmuel Shahar , Young Jessica , Girman Cynthia
Published: May 2022

Purpose

To describe the creation of prevalent new user (PNU) cohorts and compare the relative bias and computational efficiency of several alternative analytic and matching approaches in PNU studies.

Methods

In a simulated cohort, we estimated the effect of a treatment of interest vs a comparator among those who switched to the treatment of interest using the originally proposed time‐conditional propensity score (TCPS) matching, standardized morbidity ratio weighting (SMRW), disease risk scores (DRS), and several alternative propensity score matching approaches. For each analytic method, we compared the average RR (across 2000 replicates) to the known risk ratio (RR) of 1.00.

Results

SMRW and DRS yielded unbiased results (RR = 0.998 and 0.997, respectively). TCPS matching with replacement was also unbiased (RR = 0.999). TCPS matching without replacement was unbiased when matches were identified starting with patients with the shortest treatment history as initially proposed (RR = 0.999), but it resulted in very slight bias (RR = 0.983) when starting with patients with the longest treatment history. Similarly, creating a match pool without replacement starting with patients with the shortest treatment history yielded an unbiased estimate (RR = 0.997), but matching with the longest treatment history first resulted in substantial bias (RR = 0.903). The most biased strategy was matching after selecting one random comparator observation per individual that continued on the comparator (RR = 0.802).

Conclusions

Multiple analytic methods can estimate treatment effects without bias in a PNU cohort. Still, researchers should be wary of introducing bias when selecting controls for complex matching strategies beyond the initially proposed TCPS.
“Particle‐on‐plane” hybrid of ZnO‐reduced graphene oxide: Roles on mechanical and tribological performances of thermosetting polyimide
Authors: Luo Rong , He Yan , Liu Hong , Wang Jinqing , Yang Shengrong
Published: May 2022

In this article, a hybrid of reduced graphene oxide (rGO) sheets decorated by zinc oxide (ZnO) particles was synthesized by a simple hydrothermal method, and its thermosetting polyimide (TPI) composites were prepared by an in situ polymerization method. The mechanical and tribological properties of the ZnO–rGO/TPI composite under dry sliding conditions were studied. The compression strength and modulus of 0.8 wt% ZnO–rGO/TPI composite reached 120.67 ± 2 MPa and 1.77 ± 0.06 GPa, which were 28.1% and 51.3% higher than those of TPI, respectively. The wear rate of 0.8 wt% ZnO–rGO/TPI was also reduced to 1.54 × 10−8 mm3 N−1 m−1 at 100 N load, which is about two order of magnitude lower than that of TPI. Compared with the addition of GO alone, the results also demonstrate more significant enhancements in mechanical and tribological properties of TPI by ZnO–rGO hybrid. Furthermore, the tribological mechanism exploration indicates that the “particle‐on‐plane” structure and chemical bonding between ZnO and rGO lead to the crack suppression and strength increment, contributing to the extraordinary improvement of mechanical and tribological properties. Thus, this ZnO–rGO/TPI composite presents promising potential as high‐performance tribological materials under dry‐sliding conditions in industrial applications.
Processability and physico‐mechanical properties of ultrahigh‐molecular‐weight polyethylene using low‐molecular‐weight olefin wax
Authors: Bakshi Ashok Kumar , Ghosh Anup K.
Published: May 2022

The influence of molecular weight of olefin wax as a plasticizer on the processability and properties of ultrahigh‐molecular‐weight polyethylene (UHMWPE) was thoroughly investigated in this study. Two different grades of olefin wax (H5 and 210P) were used separately to plasticize UHMWPE. Comparative results were analyzed based on mixing torque, mechanical, thermal, thermo‐mechanical, and morphological aspects. The Gaussian mathematical model was applied to the internal thermo‐shear batch mixing torque data to predict processability and plasticization of the resulting compounds. A decrease in the peak torque value with increase in wax content revealed the plasticization effect. Across both types of wax (H5 and 210P) at 4, 8, and 10 phr content, the 10 phr H5 wax plasticized UHMWPE batch showed a minimum peak torque of 4.5 Nm with a broad mixing temperature window (∆T) of 32.4°C. The relatively low‐molecular‐weight wax (H5) seemed to be more efficient at uncoiling the entanglements among the amorphous phase of UHMWPE, perhaps because of its smooth interpenetration between ties. The lowest degree of crystallinity range (34%–40%) and the highest nucleation rate (0.9 min−1) were found with 10 phr H5 wax plasticized UHMWPE. The tensile strength of 30.5 MPa and elastic modulus of 127 MPa, achieved by the addition of H5 wax at 10 phr loading, confirmed the optimum effect of plasticization. The plasticization effect was also established from the loss moduli and Cole–Cole plots (log loss modulus vs. log storage modulus). A smaller number of multiple stress‐induced overshoots and the inclining approach toward the viscous dominant regime with temperature sweep were observed in the case of 10 phr H5 wax composition. Scanning electron microscopy (SEM) analysis revealed disappearance of interfacial crazing and interparticle boundaries progressively with the increase in H5 wax content. Overall, plasticized UHMWPE with 10 phr content of H5 wax showed the optimum processability and properties.
Silicon solar cells with passivating contacts: Classification and performance
Authors: Yan Di , Cuevas Andres , Stuckelberger Josua , Wang Er‐Chien , Phang Sieu Pheng , Kho Teng Choon , Michel Jesús Ibarra , Macdonald Daniel , Bullock James
Published: May 2022

The year 2014 marks the point when silicon solar cells surpassed the 25% efficiency mark. Since then, all devices exceeding this mark, both small and large area, with contacts on both sides of the silicon wafer or just at the back, have utilized at least one passivating contact. Here, a passivating contact is defined as a group of layers that simultaneously provide selective conduction of charge carriers and effective passivation of the silicon surface. The widespread success of passivating contacts has prompted increased research into ways in which carrier‐selective junctions can be formed, yielding a diverse range of approaches. This paper seeks to classify passivating contact solar cells into three families, according to the material used for charge‐carrier selection: doped amorphous silicon, doped polycrystalline silicon, and metal compounds/organic materials. The paper tabulates their current efficiency values, discusses distinctive features, advantages, and limitations, and highlights promising opportunities going forth towards even higher conversion efficiencies.
A theory of finite tensile deformation of double‐network hydrogels
Authors: Shams Es‐haghi Siamak , Weiss Robert A.
Published: May 2022

A continuum damage model was developed to describe the finite tensile deformation of tough double‐network (DN) hydrogels synthesized by polymerization of a water‐soluble monomer inside a highly crosslinked rigid polyelectrolyte network. Damage evolution in DN hydrogels was characterized by performing loading‐unloading tensile tests and oscillatory shear rheometry on DN hydrogels synthesized from 3‐sulfopropyl acrylate potassium salt (SAPS) and acrylamide (AAm). The model can explain all the mechanical features of finite tensile deformation of DN hydrogels, including idealized Mullins effect and permanent set observed after unloading, qualitatively and quantitatively. The constitutive equation can describe the finite elasto‐plastic tensile behavior of DN hydrogels without resorting to a yield function. It was showed that tensile mechanics of DN hydrogels in the model is controlled by two material parameters which are related to the elastic moduli of first and second networks. In effect, the ratio of these two parameters is a dimensionless number that controls the behavior of material. The model can capture the stable branch of material response during neck propagation where engineering stress becomes constant. Consistent with experimental data, by increasing the elastic modulus of the second network the finite tensile behavior of the DN hydrogel changes from necking to strain hardening.
Development of an analysis and testing concept for the evaluation of impact targets in the mechanical safety testing of dangerous goods packagings
Authors: Lengas Nikolaos , Müller Karsten , Schlick‐Hasper Eva , Neitsch Marcel , Johann Sergej , Zehn Manfred
Published: May 2022

The mechanical and geometrical properties of impact targets greatly influence the outcome of a drop test. The International Agreement concerning the International Carriage of Dangerous Goods by Road (ADR) as well as ISO 2248 describe the characteristics of impact targets for drop tests of dangerous goods packagings. According to these regulations, the impact target's surface needs to be unyielding, under testing conditions non‐deformable, flat and integral with a mass at least 50 times that of the heaviest packaging to be tested. The problem is that many production facilities, especially manufacturers of corrugated fibreboard boxes, do not have their own testing device with the required 50 times mass ratio of the impact target for a regulation compliant drop test during series production. Furthermore, at UN level, it is considered necessary to revise these requirements. In the present paper, the impact target requirements are examined in detail and compared with those in other technical areas (e.g., impact target for container for the transport of radioactive materials). A research method is being developed to investigate the dependency between the mass ratio of the packaging and the target as well as the damage resistance of a drop tested package in relation to specific design characteristics. The results are of high relevance for industry purposes and intended to ensure a uniform level of safety assessment for the mechanical testing of dangerous goods packagings.
Effective buoyancy and CAPE: Some implications for tropical cyclones
Authors: Smith R. K. , Montgomery M. T.
Published: May 2022

We review the widely used concepts of “buoyancy” and “convective available potential energy” (CAPE) in relation to deep convection in tropical cyclones and discuss their limitations. A fact easily forgotten in applying these concepts is that the buoyancy force of an air parcel, as often defined, is non‐unique because it depends on the arbitrary definition of a reference density field. However, when calculating CAPE, the buoyancy of a lifted air parcel is related to the specific reference density field along a vertical column passing through that parcel. Both concepts can be generalized for a vortical flow and to slantwise ascent of a lifted air parcel in such a flow. In all cases, the air parcel is assumed to have infinitely small dimensions. In this article, we explore the consequences of generalizing buoyancy and CAPE for buoyant regions of finite size that perturb the pressure field in their immediate environment. Quantitative calculations of effective buoyancy, defined as the sum of the conventional buoyancy and the static vertical perturbation pressure gradient force induced by it, are shown for buoyant regions of finite width. For a judicious choice of reference density, the effective buoyancy per unit mass is essentially a unique force, independent of the reference density, but its distribution depends on the horizontal scale of the buoyant region. A corresponding concept of “effective CAPE” is introduced and its relevance to deep convection in tropical cyclones is discussed. The study is conceived as a first step to understanding the decreasing ability of inner‐core deep convection in tropical cyclones to ventilate the mass of air converging in the frictional boundary layer as the vortex matures and decays.
Varicella‐zoster virus pneumonia co‐infected with Pneumocystis jirovecii
Authors: Zhang Qianwen , Liang Lingxiao , Liu Ailing , Zhou Dandan , Li Aijun
Published: May 2022

Key message

Pulmonary co‐infection with varicella‐zoster virus (VZV) and Pneumocystis jirovecii (PJ) is uncommon. This case describes computed tomography (CT) findings of VZV pneumonia co‐infected with PJ. Co‐infection of VZV and PJ pneumonia is possible in immunocompromised patients. The similarities in chest CT makes it difficult to differentiate VZV from PJ.
Decentralized adaptive output feedback dynamic surface control for stochastic nonstrict‐feedback interconnected nonlinear systems with actuator failures and input quantization via command filter
Authors: Zhang Tianping , Tang Hailin , Xia Xiaonan , Yi Yang
Published: May 2022

In this article, a new decentralized adaptive neural output feedback control scheme based on first‐order command filter is proposed for stochastic nonstrict‐feedback interconnected systems with prescribed performance, input quantization, actuator failures and unmodeled dynamics. The unknown smooth functions are eliminated by using the radial basis function neural networks. The immeasurable states in the system are estimated using the decentralized K‐filters, unmodeled dynamics is processed using dynamic signal, and the hyperbolic tangent function is applied to the construction of the prescribed performance function. The hysteretic quantizer and actuator failure are denoted in the form of linearization, and a smoothing function is introduced to compensate for the effects of quantization and bounded stuck faults. Based on the dynamic surface control (DSC) method and using the properties of Gaussian function to deal with stochastic nonstrict‐feedback interconnected systems, the first‐order command filter is used to replace the first‐order filter in the traditional DSC to eliminate the influence of filtering error on the systems, and an error compensation signal is introduced at the recursive each step of the design to construct a new error dynamic surface, which simplifies the derivation process and the design of the controller. Finally, the Lyapunov method is used to prove that all the signals in the whole controlled system are semiglobally uniformly ultimately bounded in probability and the tracking error is within the time‐varying constraint. The effectiveness of the proposed decentralized adaptive control method is verified by a numerical simulation and an example simulation.
About the special issue on: “Distributed Complex Systems: Governance, Engineering, and Maintenance”
Authors: Braione Pietro , Briola Daniela , De Angelis Guglielmo , Gallo Francesco , Poggi Francesco , Quattrocchi Giovanni
Published: May 2022

The volume at hand presents the Special Issue on “Distributed Complex Systems: Governance, Engineering, and Maintenance”. The Special Issue has been originally conceived within the context of the 2nd International Workshop on Governing Adaptive and Unplanned Systems of Systems (GAUSS 2020), one of the co‐located events of the 31st International Symposium on Software Reliability Engineering (ISSRE 2020). The authors of the best papers at GAUSS 2020 have been invited to submit an extended version of their previous work. In addition, the editors opened the submission also to all the other researches working on technical and managerial solution for governing Distributed Complex Systems. Ultimate objective of the editors with this Special Issue is to promote discussions focusing on anticipating, mitigating, or reacting to scenarios that were unplanned or under‐specified at design time.
Azo‐Initiator‐Induced Cascade Defect Passivation for Efficient and Stable Planar Perovskite Solar Cells
Authors: Li Mingguang , Gao Huan , Peng Ying , Tang Senlin , Liu Ying , Deng Yong , Xu Ligang , Chen Runfeng
Published: May 2022

Remarkable progress in perovskite solar cells (PSCs) has been made by virtue of surface and bulk modification for defect control of perovskite layers, however, the interior defects in the perovskite layer can be hardly passivated by means of conventional passivation strategies, which makes perovskites prone to decomposition with inferior device performance. Here, the authors propose a cascade defect passivation strategy to doubly reduce perovskite defects by introducing a series of azo radical initiators. The primary passivation process of the azo compounds is realized on the perovskite surfaces through strong coordination interactions between Pb2+ and carbonyl/cyano groups. The secondary passivation occurs after thermal treatment, and the decomposed products diffuse into the interior defects of the initial passivated perovskite films through grain boundaries to accomplish the cascade defect passivation. Excitingly, this passivation strategy inhibits unwanted defect‐assisted recombination effectively, and thus CH3NH3PbI3 (MAPbI3)‐based inverted PSCs exhibit a significant increase in power conversion efficiency (PCE) from 16.92% to 19.69%. Moreover, the dual‐passivated PSCs show only 10% PCE loss after 3000 h in an inert atmosphere. Overall, the first proposed cascade defect passivation strategy is highly efficient in promoting defect healing of perovskites, demonstrating a new way to prepare high‐quality perovskite films for high‐performance PSCs.
SDK4ED: A platform for technical debt management
Authors: Ampatzoglou Apostolos , Chatzigeorgiou Alexander , Arvanitou Elvira Maria , Bibi Stamatia
Published: May 2022

Technical debt management is of paramount importance for the software industry, since maintenance is the costlier activity in the software development lifecycle. In this article, we present the SDK4ED platform that enables efficient technical debt management (i.e., measurement, evolution analysis, prevention, etc.) at the code level, and evaluate its capabilities in an industrial setting. The SDK4ED platform is the outcome of a 3‐year project, including several software industries. Since, the research rigor of the approaches that reside in SDK4ED have already been validated, in this work we focus: (a) on the presentation of the platform per se; (b) the evaluation of its industrial relevance; (c) the usability of the platform; as well as (d) the financial implications of its usage.
MuFBDTester: A mutation‐based test sequence generator for FBD programs implementing nuclear power plant software
Authors: Liu Lingjun , Jee Eunkyoung , Bae Doo‐Hwan
Published: May 2022

Function block diagram (FBD) is a standard programming language for programmable logic controllers (PLCs). PLCs have been widely used to develop safety‐critical systems such as nuclear reactor protection systems. It is crucial to test FBD programs for such systems effectively. This paper presents an automated test sequence generation approach using mutation testing techniques for FBD programs and the developed tool, MuFBDTester. Given an FBD program, MuFBDTester analyses the program and generates mutated programs based on mutation operators. MuFBDTester translates the given program and mutants into the input language of a satisfiability modulo theories (SMT) solver to derive a set of test sequences. The primary objective is to find the test data that can distinguish between the results of the given program and mutants. We conducted experiments with several examples including real industrial cases to evaluate the effectiveness and efficiency of our approach. With the control of test size, the results indicated that the mutation‐based test suites were statistically more effective at revealing artificial faults than structural coverage‐based test suites. Furthermore, the mutation‐based test suites detected more reproduced faults, found in industrial programs, than structural coverage‐based test suites. Compared to structural coverage‐based test generation time, the time required by MuFBDTester to generate one test sequence from industrial programs is approximately 1.3 times longer; however, it is considered to be worth paying the price for high effectiveness. Using MuFBDTester, the manual effort of creating test suites was significantly reduced from days to minutes due to automated test generation. MuFBDTester can provide highly effective test suites for FBD engineers.
Waste glass as a precursor in alkali‐activated materials: Mechanical, durability, and microstructural properties
Authors: Mobasheri Fatemeh , Mirvalad Sajjad , Shirzadi Javid Ali Akbar , Azizi Shahab , Ghoroqi Mahyar
Published: May 2022

The long‐term characteristics and durability of alkali‐activated mortars based on waste glass are crucial to better understand their performance in aggressive environments. In this regard, the performance of waste glass as a building material and its characteristics such as mechanical (compressive, flexural, and tensile strengths), durability (chloride migration coefficient, sulfate resistance, and drying shrinkage), and microstructural properties [x‐ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) with energy dispersive x‐ray analysis (SEM/EDX)] were evaluated. For this purpose, the specimens with different amounts of silica modulus and Na2O content were prepared. The specimens were cured at 95°C for 20 h and then kept at a relative humidity of 50% at room temperature until testing. The specimen with 10% Na2O and a silica modulus of 1.5 demonstrated the highest compressive, flexural, and tensile strengths. The specimens illustrated a lower chloride migration coefficient and lower expansion than the Portland cement one. By increasing both silica modulus and Na2O contents, the drying shrinkage of the specimens increased due to the presence of more free water. The microstructural results indicated that amorphous gels such as sodium aluminum silicate hydrate (N‐A‐S‐H) and sodium (calcium) silicate aluminum hydrate [N‐(C)‐A‐S‐H] were formed. The results of this study signify the utilization possibility of waste glass as an eco‐friendly material with desirable characteristics.
Black men doctoral scientists and engineers persisting: Peer support and racism in science and engineering
Authors: Watkins Shari Earnest , McGowan Brian L.
Published: May 2022

Drawing on racial battle fatigue as theoretical framing and critical race methodology, we offer the counterstories of 16 Black men doctoral scientists and engineers who relied on same race peer support to successfully persist in their science and engineering (S&E) doctoral programs. Our analysis of narratives and interviews yielded three themes that illustrate the men's engagement with Black peers and how racism influences the types of peer relationships they formed in their S&E doctoral programs. Further, we describe three types of same race peer relationships that support Black men as they pursue S&E doctoral degrees. We underscore the salience of racism and recommend expanding research in S&E by: (1) including the lived experiences of Black men scientists and engineers in the scholarly literature, and (2) highlighting the importance of same race peer networks as academic, emotional, and social structures for Black men persisting in S&E. Within, we offer implications for science education, higher education, and S&E researchers interested in creating supportive S&E environments for Black men.
Towards a potential Paradigm Shift. The Role of Vision Zero in Global Road Safety Policy Making
Authors: Kristianssen Ann-Catrin
Published: May 2022

Vision Zero is a term mainly connected to road traffic safety and has its roots in the Swedish road safety policy, although similar concepts are used in other countries. It was adopted by the Swedish Parliament in 1997, and due to the success of lowering the number of deaths in traffic crashes significantly, it has become an inspiration to road safety strategies in countries and cities all over the world. An important factor as to why Vision Zero diffuses is the incorporation of the vision in reports and strategies from international intergovernmental organizations and through the work of nongovernmental organizations. The development of finding a common global strategy for road safety has been an ongoing process for many years, and the purpose of this chapter is to map the role of Vision Zero in this global development process. This is performed by studying the integration of Vision Zero in the road safety work and strategies of key international intergovernmental and nongovernmental organizations. The chapter also contains an account of possible opportunities and advantages of working with Vision Zero as a tool on the global level as well as the criticism towards the approach. This chapter discusses the content of what is being diffused, why it is diffused, who is diffusing, and how it is diffusing. The material consists of key global policy documents and 29 semi-structured interviews with senior experts working with road safety on a global level. The main conclusions are that Vision Zero is a well-established global road safety policy program and a road safety philosophy integrated into both the work and texts of the major intergovernmental organizations working with road safety. There is a widespread opinion that Vision Zero and other safe system approaches constitute a paradigm shift in global road safety work. It is regarded as an innovative and inspiring policy based primarily on its ethical approach. It is also regarded as a coherent policy program and rests firmly upon years of progress and experience. Even though many of the respondents are positive towards the ethical base and the systematic approach, there are still those who argue that Vision Zero cannot be used as a policy tool, at least not in low- and middle-income countries. It is obvious that Vision Zero is not interpreted and reproduced in the same way in all contexts, but the question is if that is part of a natural transformation process leading to new interpretations or if it is a problem for the Vision Zero trademark.
Rural Road Design According to the Safe System Approach
Authors: Stigson Helena , Kullgren Anders , Andersson Lars-Erik
Published: May 2022

This chapter covers design of rural roads according to the model for safe traffic used in the Vision Zero approach. Based on expected levels of the safety of vehicles and road users, the roads and the road side furniture should be designed to avoid fatalities and serious injuries. An introduction is presented covering the safe system approach and how speed limits of roads should be set to reflect the safety standard of the road in relation human injury tolerance and the capacity to protect the road users. One section will cover countermeasures to protect vulnerable road users, including speed calming road infrastructure, bicycle and pedestrian paths, bus stops. Another section will cover road infrastructure countermeasures addressing vehicle occupants. It is shown how change of velocity, vehicle mean acceleration, and crash duration are correlated and how they influence occupant injury risk. Design of different types of roads on rural roads is described, such as the two-plus-one lane road design with median barrier, and various ways of separating traffic or preventing run-off road crashes including road barrier design and rumble strips. Safe intersection design is an important part on rural roads that is explained. The last part covers design of the roadside area from a safe system approach.