bluuebunny/crossref_metadata_2025 huggingface dataset:
Common defects of parts manufactured through single point incremental forming
Authors: Popp Mihai , Rusu Gabriela , Racz Sever-Gabriel , Oleksik Valentin
Published: August 2021

Single point incremental forming is one of the most intensely researched die-less manufacturing process. This process implies the usage of a CNC equipment or a serial robot which deforms a sheet metal with the help of a relatively simple tool that follows an imposed toolpath. As every cold metal forming process, besides the many given advantages it has also some drawbacks. One big drawback in comparison with other cold metal forming processes is the low accuracy of the deformed parts. The aim of this research is to investigate the sheet metal bending mechanism through finite element method analysis. The results shows that the shape of the retaining rings has a big influence over the final geometrical accuracy of the parts manufactured through single point incremental forming.
Potential Resistance of Employees to Change in the Transition to Industry 5.0
Authors: Moraru Gina-Maria , Popa Daniela
Published: August 2021

The unprecedented evolution of the technological environment inevitably generates resistance to change in the population. The paper aims to detect these resistances in the conditions of a future transition to Industry 5.0. Firstly, we present the results of a bibliographic study of the specialized literature, in order to answer the dilemma of the existence or absence of the differences between the two concepts, that of Industry 4.0 and that of Industry 5.0. Secondly, the paper contains the results of an online survey based on a questionnaire conducted among employees in the central area of Romania. The research is related to the employees’ perception on the possible evolution of the economic environment by implementing the concept of Industry 5.0. and focuses on issues that may bother them in their professional lives. Although we found that there are many oppositions to a potential transition to Industry 5.0, we still appreciate that the accelerated evolution of technology will be able to reduce much of them, the speed of technological change being much higher than the reaction speed of employees.
Model for Industrial Business Relocation in Eastern Europe
Authors: Gheorghe Catalin , Panazan Oana
Published: August 2021

Relocation of production is an operation by which a company transfers part or all of its production capacity from one country to another or from one city to another. It is a current problem for industrial and other business, a visible consequence of the globalization of the world economy. Moving the company is an activity that involves a high consumption of resources over a long period of time so it must be treated with great responsibility. Being a long-term decision, it must be supported by research to determine all the factors involved and the effect they, individually or in groups, have on relocation. The article aims to identify, group and eliminate overlaps between the criteria considered in the literature. The paper presents a different approach compared to other research. The factors that determine the relocation based on a large number of researches have been identified. Subsequently, the factors were synthesized into 8 groups. For each group the most important measurement indicator was selected taking into account a large number of variants. 12 Eastern European countries were selected for which data were accessed on the 8 criteria used from international databases. Statistical data processing led to a multiple regression equation that allows the determination of the score obtained by each state analysed. The scores thus obtained were statistically processed and a cubic equation was established. Such relationships allow the identification of solutions that states must undertake to attract investors. The results can be used by companies, regardless of their size, as a large number of scientifically proven factors have been taken into account.
Analysis of the eigenfrequencies of the basalt machine parts by the FEM
Authors: Popp Ilie Octavian
Published: August 2021

The aim of this paper was to carry out a theoretical (numerical) scientific research on the behavior of cast and recrystallized basalt, in order to use it as a material in the manufacture of structural elements of machine tools. A unitary methodology has been established for studying the eigenfrequency of structural elements for machine tools by the finite element method. Two basalt structural elements (beam type and plate type) were modeled, which were also made physically, and with the help of the COSMOS / Mark finite element program, the eigenfrequencies of the models was studied.
Studies on mobile robots for all types of terrain
Authors: Pecie Robert Florian , Tătar Mihai Olimpiu , Rusu Călin
Published: August 2021

In the first part of the paper, the authors present the characteristics of the robots for all types of terrain. In the second part, two categories of robots are proposed: a robot with hybrid locomotion system and a modular robot. For the last category, if different modules are combined, a family of modular robots adaptable to different types of terrain can be obtained. The solutions proposed by the authors allow the study of the mobility and adaptability of robots to different types of terrain.
Aspects regarding the reduction of fugitive methane emissions from the valves
Authors: Petre Ioana , Stoica Monica Emanuela
Published: August 2021

Methane is the second strongest greenhouse gas contributing to climate change after carbon dioxide. Reducing methane emissions contributes to both slowing climate change and improving air quality. In order to reduce methane emissions from the energy sector, the European Commission has proposed the obligation to improve leak detection and disposal in fossil fuel infrastructure, as well as any other infrastructure that produces, transports or uses fossil fuels. Compressors and compressor stations are such a component of the energy system. The paper presents the testing procedures of the valves in the gas transmission pipes for the evaluation of external leaks and the proposed corrective actions to minimize them.
Shifting towards Proactive OHS Risk Management in Romanian Organizations: Systematic Benchmarks
Authors: Moraru Roland Iosif , Băbuţ Gabriel Bujor , Popescu – Stelea Mihai , Szabo Zoltan-Gyozo
Published: August 2021

As they are anticipative, proactive, and treating assessment as a quasi-continuous phase of risk management, the next step in keeping workers safe seems to be the proper implementation of the guidelines on risk assessments included in ISO 45001. They are indeed inspiring for organizations worldwide to consider risk management as really important, good for the business, and imperative for worker health and safety. What should the Romanian organizations know and do in this spirit? The main objective of this paper is to answer systematically and in a structured way the question of whether there is a set of principles, means to follow, recommendable approaches that, taking into account the general practice established at national level at this time of evolution, allow even to facilitate the transition from reactive to proactive management of occupational hazards, with all the advantages and - at the same time - challenges that this change implies? The main possible answers to this question are investigated, resulting in a set of conclusions with practical applicability, which can guide the process of streamlining the results of accidents at work and occupational diseases prevention work at the national level, within a coherent and unitary vision.
Assessment of the risk of loss of hearing generated by the hazardous exposures during the work process
Authors: Vochitoiu Haralambie , Unguras Camelia Lavinia , Popa Narcis Nicolae , Pintilie Dan Dumitru , Huber Philippe Yves Daniel , Darcy Anton , Ilcea Gabriel Ioan
Published: August 2021

This research presents an integrated methodological approach to probabilistic / statistical analysis and assessment of the risk of hearing loss, taking into account the dangers expressed as risk predictors, in order to establish ways to determine the prudential limits corresponding to the value areas of acceptability. Statistical evaluation is based on the rational quantification of the observable reality, the probabilistic part of this fact being the extrapolation to what can be reasonably deduced from these statistics for the assessment of the probability of hearing impairment.
Virtual ignition of a methane leak by electric spark
Authors: Vlasin Nicolae-Ioan , Ghicioi Emilian , Păsculescu Vlad Mihai , Morar Marius Simion , Munteanu Laurenţiu
Published: August 2021

In the virtual environment, respectively in a rectangular tube with a hole at one end, a computational simulation was performed comprising two stages: the first stage aims at simulating a methane gas leak through a hole in the floor of the tube and its diffusion in the air of which the inner volume of the virtual environment is constituted. At the full end of the tube is arranged an electric ignition source that activates in parallel with the gas source, being observed the formation of the explosive mixture in the proximity of the ignition source and the moment of initiation of the explosive atmosphere. The second stage of the simulation is marked by a higher level of velocities characteristic of the explosive process of the airmethane mixture, which involves the use of different settings. The host of the computer simulation is the Fluent application of the ANSYS platform. Post-processing is performed both on the ANSYS platform, through the Fluent and Results applications and through the facilities offered by the Tecplot 360 application.
Phosphating Depositions for Equipment’s Used in Explosive Atmospheres
Authors: Burduhos-Nergis Diana-Petronela , Jurca Adrian-Marius , Popa Catalin-Mihai , Cimpoesu Ramona , Darabont Doru-Costin , Bejinariu Costica
Published: August 2021

According to the ATEX directive, any personal protective equipment or work equipment intended to be used in a potentially explosive area must be made of materials that cannot be the source of mechanical or static electricity-related sparks. The carbon steel is one of the most widely used metallic materials, but the possibility of using it in the manufacture of equipment used in explosive environments is low. Therefore, the purpose of this article is to present an alternative solution to use metal equipment in potentially explosive atmospheres, by depositing a phosphate layer on the surface of the carbon steel. The metal was coated by a simple process, the metal being immersed in a phosphating solution based on zinc. Due to the properties of zinc phosphate deposited on the steel surface, especially electrical insulating, the steel coated with this type of layer can be used in explosive atmosphere.
Risks assessment in terms of OHS for critical power infrastructures in context of industrial safety
Authors: Pasculescu Dragos , Fita Nicolae Daniel , Grigorie Emilia , Popescu Florin Gabriel , Handra Alina Daniela
Published: August 2021

The aim of occupational health and safety in the context of industrial safety is to provide the national industry with a proper operation state, an ergonomic, optimal and healthy work environment, safe workers and workplaces, safety of industrial processes, to limit and mitigate any unforeseen situation generated by events which might negatively affect the occupational health and safety level. The current paper approaches the risk assessment in terms of occupational health and safety within a cross-border 400/220 kV power substation interconnected to the European power grid, identified and assigned as European critical infrastructure. The assessment is carried out using the INCDPM Bucharest method, in order to establish the risk/safety levels in a quantitative manner, based on a systemic analysis and on the assessment of risks of accidents and professional diseases. The application of the method ends in a workplace assessment sheet which comprises the global risk level of the power substation and which sets the grounds for the plan for preventing accidents and professional diseases within the analysed power substation.
An important challenge in occupational health: sampling indoor airborne viruses
Authors: Cocârţă Diana M. , Gogoncea Cristina A. , Streche Constantin
Published: August 2021

Airborne biological particles are made by bacteria, viruses, fungi, pollen, dust mites and other living organisms. Between the airborne biological contaminants, the sampling of airborne viruses is the most difficult. This technical challenge has real consequences both in limiting the studies on the aerobiology of viral diseases, and in making possible, at least for now, to establish Standards for Acceptable Bioaerosol Exposure Limits in case of viruses. The circumstances and uncertainties in which we are living from the end of 2019, have demonstrated once again, the need of having common approaches in sampling, processing, and analysis of bioaerosol samples. Results from sampling indoor airborne viruses can be used both for identifying the airborne transmission of the respiratory viruses and for providing useful information as support in human health risk assessments. On the other hand, even if there are different sampling methods and equipment used for collecting bioaerosols, there are certain elements that must be considered in choosing the most appropriate sampling method to collect airborne viruses. The main challenge in sampling indoor airborne viruses is to identify the system that allows the sampling of bioaerosols ensuring in the same time the viability of the virus and the representativeness of the sample. Keeping in mind the lack of standardization in sampling indoor airborne viruses, as well as the missing of common approaches for air sampling strategies or sample treatment and analysis, the present work is focused on providing important recommendations as support in the concentrated effort of the researchers in developing of a common strategy for indoor viable bioaerosol sampling for virus detection.
Is organizational skill a will or a way to a successful lifestyle and workstyle?
Authors: Bratu Mihaela Laura , Cioca Lucian Ionel
Published: August 2021

Organizational skill is a transversal competence, which is formed through concrete life experiences. On the labour market, organizations want high-performing employees with developed organizational skills. The approach of training the organizational competence is inductive, starting from personal life, competence formed through voluntary exercise, and continuing by practicing and improving it during school life and at work, through ways offered by academic education and management, but also through organizational skill management. This paper aims to analyse the concept of organizational skill, from the perspective of mental mechanisms involved in its formation, as well as human resource management strategies, applied at the level of university education. Approaching the organizational skill from both perspectives, the competence will lead to a new lifestyle and workstyle oriented towards performance and success. The level of organizational skill of students was analysed, based on a questionnaire to assess organizational competence and a practical test of organization. Following the analysis of the results, it was observed that a small number of young people are very well organized, and their resistance to change is quite high. Finally, the study offers possible school management strategies for training and developing organizational skills, leading to a successful lifestyle and work.
Intelligent learning environment for better student’s academic performance
Authors: Vişan Anca–Elena , Zerbes Mihai–Victor , Kifor Ştefania
Published: August 2021

In this paper, the authors aim to develop an intelligent learning environment model designed to improve students’ academic performance. Methodology: Referring to the litarature, the authors identified and analyzed a number of relevant issues that influence the specific components of an intelligent learning environment. These aspects were quantified using performance indicators defined on the basis of the specific objectives of each aspect chosen. Results: Following the analysis, the authors developed a model of intelligent learning space, and for its representation, we used conceptual modeling. Conclusions: Finally, the authors propose the prevalidation of the model using the dynamic modeling process and then the model will be piloted for final validation in both physical and virtual environment. These aspects are proposed because in the present study, the model was validated only based on the results from studies in scientific literature.
A brief analysis of eLearning educational services in pandemic crisis
Authors: Petre Ioana
Published: August 2021

The paper presents an analysis of the online education, in the pandemic crisis. Technology provides innovative solutions in the human interactions and the education should benefit by these. The pandemic crisis we all are passing forced education actors to reconsider teaching and learning using online learning. ELearning has an increased importance in these moments, so, in this paper is made an analysis of the strengths and weaknesses of this type of education, as well as the opportunities and threats that may occur. Some challenges were identified that the crisis came with, in educational domain. The results highlighted that the strategy that should be adopted by the educational institutions must be based on an intensive use of the educational platforms in online environment. Some proposals has been made such as the need for quality improvement activities in online teaching or a resource planning for saving time and optimizing the organizational learning process.
Multimedia Competencies for University Staff to Empower Manufacturing Science Education
Authors: Draghici Anca
Published: August 2021

The paper aims describing a collaborative international initiative of four European universities to develop a training program for supporting university staff in creating and using multimedia resources effectively. Thus, teaching, researcher and administrative staff from higher education institutions will develop their digital skills to create more realistic and attractive content that should improve university prestige through a better communication process with the stakeholders. We relate the presented approach to MUST project (Multimedia Competencies for University Staff to Empower University - Community Collaborations, 2020-1-RO01-KA203-080399), that aims develop and implement a new multimedia curriculum and training program. The training curriculum and the created educational resources make up a dedicated service offered by universities through DigiCoaches who will provide training to other internal/external users/trainees in creating-using multimedia technologies effectively.
Centralized resource allocation with the possibility of downsizing in two-stage network production systems
Authors: Yadolladi Amir Hossein , Kazemi Matin Reza
Published: August 2021

The network data envelopment analysis (NDEA) technique has been recently developed to measure the relative efficiency of complex production systems. NDEA models provide more meaningful and informative results in comparison to the conventional black-box DEA approach that ignores the operations of the component processes. Regarding the centralized decision-making systems, normal management imposes common resource constraints to maximize produced outputs and minimize consumed inputs. The present study seeks to introduce new centralized resource allocation models in two-stage network production systems. This intra-organizational perspective also provides the possibility of closing down some of the existing units to improve system efficiency. To do so, three scenarios of centralized DEA models are introduced to take advantage of this possibility. A simple numerical example is used for illustration purposes. An empirical application of the proposed approach to the twenty branches of a university is also presented to show the applicability of the new approach.
Forensische und strafrechtliche Konsequenzen des Missbrauchs von Stimulanzien
Authors: Dominik Philipp , Waßmer Martin P. , Soyka Michael , Franke Andreas G.
Published: August 2021

Pharmakologisches Neuroenhancement (PN) beschreibt die Einnahme diverser psychotroper Substanzen zur geistigen Leistungssteigerung, ohne dass dafür eine medizinische Notwendigkeit bestünde. Dazu werden vor allem Stimulanzien (Methylxanthintyp wie Koffein und Amphetamintyp wie Methylphenidat, Amphetamine) sowie Nichtstimulanzien (z. B. Antidementiva, Antidepressiva und Phytopharmaka wie Ginkgo biloba) sowie Modafinil ge- bzw. missbraucht. Auch wenn die rechtliche Situation facettenreich ist, indiziert die Einnahme von Substanzen, die zum PN eingenommen werden, nicht stets die Anwendung des Strafrechts. Sowohl die indikationslose Einnahme von frei erhältlichen Over-the-Counter-Drugs (OTC-Drugs) sowie verschreibungspflichtigen Substanzen als auch von Betäubungsmitteln ist bislang weitgehend straffrei.
Missbrauch und Abhängigkeit von Benzodiazepinen und Z-Drugs
Authors: Soyka Michael
Published: August 2021

Missbrauch und Abhängigkeit von Sedativa und Hypnotika sind klinisch häufig (Prävalenz ca. 2%), insbesondere von Benzodiazepinen und Non-Benzodiazepin-Hypnotika (Z-Drugs). Beide Substanzgruppen haben ältere und weit toxischere Sedativa und Hypnotika wie Barbiturate und Meprobamat zu Recht verdrängt. Benzodiazepine wie Z-Drugs entfalten ihre Wirkung über den inhibitorischen GABA-Rezeptor und können beide eine erhebliche Toleranz induzieren, was klinisch zu Dosissteigerungen, physischer und psychischer Abhängigkeit, Kontrollverlust sowie Entzugssymptomen führen kann. Prädisponierende Faktoren sind neben dem Geschlecht, Frauen sind häufiger betroffen, vor allem psychiatrische und psychosomatische Erkrankungen, insbesondere Angst und Schlafstörungen, aber auch psychosomatische Störungen und chronische Schmerzerkrankungen. Besonders häufig und lange werden Benzodiazepine älteren Patienten verschrieben, entgegen aller Leitlinienempfehlungen.

Therapeutisch gesichert ist, dass bei Benzodiazepinabhängig-keit ein langsames Ausschleichen über viele Wochen, manchmal sogar Monate notwendig ist. Ansonsten können erhebliche Entzugserscheinungen inklusive epileptischen Anfällen, Psychosen und Delire auftreten. Das Entzugssyndrom bei Sedativa und Hypnotika ist sehr vielgestaltig mit Depression, Agitation, innerer Unruhe und Perzeptions-und Schlafstörungen als häufigen Symptomen. Die übrige Therapie ist pragmatisch und richtet sich nach den zugrunde liegenden psychischen Störungen und Entzugssymptomen. Im Wesentlichen werden Antidepressiva eingesetzt. Kurzzeitinterventionen werden empfohlen. Psychotherapeutisch haben sich Psychoedukation, kognitive Verhaltenstherapie oder motivationale Therapien bewährt.
Availability of interventional-radiological revascularization procedures in Germany – an analysis of the DeGIR Registry Data 2018/19
Authors: Mahnken Andreas H. , Nadjiri Jonathan , Schachtner Balthasar , Bücker Arno , Heuser Lothar J. , Morhard Dominik , Landwehr Peter , Hoffmann Ralf-Thorsten , Berlis Ansgar , Katoh Marcus , Reimer Peter , Ingrisch Michael , Paprottka Philipp
Published: August 2021

Purpose Peripheral artery disease (PAD) is a common condition with high socio-economic relevance. Therefore, qualified nationwide provision of interventional treatments of PAD is important for maintaining a high quality medical service in Germany.

Materials and Methods All data on revascularization procedures from the quality management system of the German interventional radiological society (DeGIR) for the years 2018 and 2019 were retrospectively analysed. Number and distribution of DeGIR certified endovascular specialists and treatment centres was mapped. Documented procedures were broken down to the level of administrative districts. Absolute number of revascularization procedures and normalized number per one million inhabitants were computed.

Results In 2019 there were 57 732 revascularization procedures from 228 participating centres performed by DeGIR certified interventional radiologists. A median of 62 recanalization procedures were documented per centre. 36 centres were considered to be high volume centres, with more than 500 procedures each. On a regional level in the years 2018 and 2019 combined a median (range) of 2324 (323–12 518) revascularization procedures per administrative district were performed by DeGIR certified interventional radiologist.

Conclusion There is a comprehensive nationwide high quality interventional-radiology service for the provision of revascularization procedures available in Germany.

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Citation Format
Assessing Data Adequacy for High Blood Pressure Clinical Decision Support: A Quantitative Analysis
Authors: Dorr David A. , D'Autremont Christopher , Pizzimenti Christie , Weiskopf Nicole , Rope Robert , Kassakian Steven , Richardson Joshua E. , McClure Rob , Eisenberg Floyd
Published: August 2021

Objective This study examines guideline-based high blood pressure (HBP) and hypertension recommendations and evaluates the suitability and adequacy of the data and logic required for a Fast Healthcare Interoperable Resources (FHIR)-based, patient-facing clinical decision support (CDS) HBP application. HBP is a major predictor of adverse health events, including stroke, myocardial infarction, and kidney disease. Multiple guidelines recommend interventions to lower blood pressure, but implementation requires patient-centered approaches, including patient-facing CDS tools.

Methods We defined concept sets needed to measure adherence to 71 recommendations drawn from eight HBP guidelines. We measured data quality for these concepts for two cohorts (HBP screening and HBP diagnosed) from electronic health record (EHR) data, including four use cases (screening, nonpharmacologic interventions, pharmacologic interventions, and adverse events) for CDS.

Results We identified 102,443 people with diagnosed and 58,990 with undiagnosed HBP. We found that 21/35 (60%) of required concept sets were unused or inaccurate, with only 259 (25.3%) of 1,101 codes used. Use cases showed high inclusion (0.9–11.2%), low exclusion (0–0.1%), and missing patient-specific context (up to 65.6%), leading to data in 2/4 use cases being insufficient for accurate alerting.

Discussion Data quality from the EHR required to implement recommendations for HBP is highly inconsistent, reflecting a fragmented health care system and incomplete implementation of standard terminologies and workflows. Although imperfect, data were deemed adequate for two test use cases.

Conclusion Current data quality allows for further development of patient-facing FHIR HBP tools, but extensive validation and testing is required to assure precision and avoid unintended consequences.
Challenges in Managing Massive Neck Pseudoaneurysm
Authors: V. Bharath , Agasty Sumit , Hote Milind Padmakar
Published: August 2021

Pseudoaneurysms in the neck are challenging surgical cases. They need detailed preoperative evaluation, treatment of etiology, and surgical/interventional management at appropriate time.

Here, we describe a case of 45-year-old female who presented to emergency with impending rupture of swelling in the right side of neck. On evaluation, it was found to be a pseudoaneurysm of right common carotid artery (RCCA). She was planned for emergency surgery, but the swelling ruptured before the patient could be taken into the operation room (OR). The challenges faced in managing it are described below.
Pulmonary Arterial Dilatation: Imaging Evaluation Using Multidetector Computed Tomography
Authors: Raju Sreenivasa Narayana , Pandey Niraj Nirmal , Sharma Arun , Malhi Amarinder Singh , Deepti Siddharthan , Kumar Sanjeev
Published: August 2021

Pulmonary artery dilatation comprises a heterogeneous group of disorders. Early diagnosis is important as the presentation may be incidental, chronic, or acute and life threatening depending upon the etiology. Cross-sectional imaging plays an important role, with CT pulmonary angiography being regarded as the first line investigation in the evaluation of pulmonary artery pathologies. Moreover, effects of pulmonary artery lesions on proximal and distal circulation can also be ascertained with the detection of associated conditions. Special attention should also be given to the left main coronary artery and the trachea-bronchial tree as they may be extrinsically compressed by the dilated pulmonary artery. In context of an appropriate clinical background, CT pulmonary angiography also helps in treatment planning, prognostication, and follow-up of these patients. This review mainly deals with imaging evaluation of the pulmonary arterial dilatations on CT with emphasis on the gamut of etiologies in the adult as well as pediatric populations.
Atypical Intratemporal Meningioma Masquerading as Otitis Media—Clinical and Radiological Diagnostic Dilemma
Authors: Matish Mrinal , Rathi Abhishek , Moon Manasi
Published: August 2021

Meningiomas are the most common intracranial extra-axial neoplasms with mostly straightforward radiological diagnosis; however, they can have unusual clinical and imaging manifestations posing diagnostic dilemma for radiologists and clinicians. The objective of this case report is to highlight the infrequent and misleading presentations of meningiomas to make an accurate diagnosis. A 65-year-old male patient presented with complaints of left recurrent otitis media and facial nerve palsy for past 6 months. On imaging, an aggressive predominantly cystic intracranial neoplasm was found in the left temporal fossa extending into the middle and external ear. Histopathological examination of the excised tumor revealed WHO grade I meningothelial meningioma. Meningiomas can show atypical imaging features such as large meningeal cysts, heterogenous or ring enhancement and aggressive features such as bone erosion. They can invade the middle ear and should be thought of while dealing with nonresponsive cases of otitis media.
‘If She’s Pregnant, then that Means that Her Dreams Fade Away’: Exploring Experiences of Adolescent Pregnancy and Motherhood in Rwanda
Authors: Coast Ernestina , Mwali Marie Merci , Isimbi Roberte , Ngabonzima Ernest , Pereznieto Paola , Buzby Serafina , Dutton Rebecca , Baird Sarah
Published: August 2021

Adolescent motherhood can alter the future opportunities available to girls and the challenges they face. This article considers how adolescents’ capabilities are influenced by pregnancy and motherhood, using a mixed-methods case study of Rwanda. Adolescent motherhood impacts girls’ lives across multiple capabilities including education, psychosocial well-being, voice and agency, and economic empowerment. Rarely were adolescent mothers in our sample supported to return to school, for instance. Their pregnancy and motherhood were stigmatised by their families, peers, wider community and service providers. The psychosocial consequences of adolescent motherhood are significant, linked to social isolation and multifaceted stressors, including poverty. Despite recent policy and service improvements, adolescent mothers continue to be left behind.
3D-imaging of polycrystal texture, boundaries using time-domain Brillouin scattering
Authors: Bandari Anashe
Published: August 2021

Textural changes, boundaries and interfaces can be characterized at extreme conditions with modifications to the light scattering technique.
Organic-quantum dot hybrid interfaces and their role in photon fission/fusion applications
Authors: Gray Victor , Allardice Jesse R. , Zhang Zhilong , Rao Akshay
Published: August 2021

Solar energy is rapidly becoming a more important aspect in today's energy systems, and solar cells are playing a major role in this shift. However, to further boost the efficiency of conventional solar cells, fundamental thermodynamic limits must be overcome. Photon fission and photon fusion, also known as photon downconversion and photon upconversion, are gaining increasing attention as a means to improve solar energy harvesting in solar cells by overcoming thermalization and transmission losses, respectively. Important developments in these fields include the use of organic–inorganic hybrid materials that can leverage the advantages of each material. In this review, we look at the development of organic–quantum dot (QD) hybrid materials and their use as components of photon fission and fusion systems. We put a particular focus on the triplet energy transfer across these organic–inorganic hybrid interfaces and how this understanding has been developed. In the later part of the review, we focus on the recent examples of these hybrid materials as crucial components in solar energy harvesting applications based on triplet–triplet annihilation photon upconversion or singlet-fission–based photon multiplication. By highlighting the most relevant discoveries toward understanding and designing organic-QD hybrid interfaces for photon fission and fusion applications, we establish a starting point for researchers to continue moving this research field forward toward practical applications.
Development of a hydraulically controlled piston-pressurized pulsed water jet device and its application potential for hard rock breaking
Authors: Ling Yuanfei , Ge Zhaolong , Tang Jiren , Lu Yiyu , Zhang Yangkai , Wang Lei
Published: August 2021

To improve the efficiency of hard rock breaking by a pulsed water jet (PWJ), a hydraulically controlled piston-pressurized PWJ (HCPPPWJ) device has been developed, by which the large amplitude pressurization of the jet could be realized through the motion coupling of the piston and the valve core inside the device without requiring additional control or ultra-high-pressure components. Under the continuous injection of low-pressure hydraulic oil, the device has a stable pressurization effect and controllable pulse pressure and pulse frequency. The jet pressure varies periodically with the alternation of high and low pressures; in the rising stage of the pulse pressure, the jet morphology presents an umbrella-like thin-layer structure, which ensures an effective initial impact force of the jet in contact with the target. With the addition of high-frequency stress waves and water wedge pressure, local flaky exfoliation was observed when the granite surface was eroded, and the maximum radius and volume of the erosion pit were greater than those in the case of employing a continuous water jet. Compared with the interrupted PWJ, the HCPPPWJ efficiently utilizes the jet energy during the erosion process, and the specific energy is lower. The results prove that the HCPPPWJ device is an advanced tool in the field of hard rock breaking.
A reactive hydrodynamic simulation of noise propagation for a concrete-confined detonation
Authors: Ji Juntae , Lee Younghun , Yoh Jack J.
Published: August 2021

When a point source detonation occurs, high temperature and pressure gases are released and then propagate through the open atmosphere as a blast wave. This leads to an explosive sound in the form of environmental noise, which has been known to cause hearing damage to nearby residents surrounding the explosion area. In an effort to reduce such noise levels, explosion test sites are installed with sound barriers to mitigate and minimize the noise associated with the blasts. In this study, realistic explosion pressure was calculated at an initial detonation source inside a concrete sound barrier, and a numerical prediction was made to evaluate the environmental noise propagation in an actual terrain. In particular, we applied the concrete equation of state to the governing conservation equations for a spherical detonation in a confined geometry and compared the experimental data taken within 3 m from the test site and a few kilometers away from the sound source. Moreover, the amount of noise reduction was predicted by first considering the absorbed explosion pressure by the sound barrier, which later dissipated at a far distance at which the noise propagation in an actual terrain was compared with the measurements.
Quantitative correlation of hot electron emission to Auger recombination in the active region of c-plane blue III-N LEDs
Authors: Ho Wan Ying , Chow Yi Chao , Myers Daniel J. , Wu Feng , Peretti Jacques , Weisbuch Claude , Speck James S.
Published: August 2021

Using electron emission spectroscopy, measurement and analysis were conducted on the energy distribution of vacuum emitted electrons from an electrically driven InGaN/GaN commercial blue c-plane (peak wavelengths λ≈465 nm) light emitting diode (LED) with 60 nm of p-GaN on top of the active region. The signal-to-noise ratio of semiconductor peaks is improved on the thin p-GaN LED compared to previously published data on thicker p-GaN samples and is attributed to reduced loss of electrons en route to emission into vacuum during transit through the p-GaN. This further proves that hot electrons are generated in the bulk region and not by light or other hot electron generation mechanisms at the surface. Using square root of the light output power as a proxy for the active region carrier density, n, the hot electron integrated peak intensity is shown to be proportional to n3 and, thus, is directly attributed to a 3-body Auger process. Since there are significant Auger recombination currents even at low injection current densities, it is expected that Auger recombination current will dominate over radiation recombination and Shockley–Read–Hall (SRH) currents at higher current densities. This identifies Auger recombination as the dominant cause of efficiency droop.
Simulation of high-power microwaves gas breakdown with a modified multi-physical model
Authors: Zhang Tiancheng , Bao Huaguang , Ding Dazhi , Chen Rushan
Published: August 2021

In this paper, a modified multi-physics method for transient analysis of high-power microwaves (HPM) gas breakdown is proposed. Distinguished from previous works, the proposed method couples the plasma fluid equations with Maxwell's equations to fully consider the interaction between plasma and electromagnetic waves. To perform the numerical simulation, the spectral-element time-domain method is employed, which has the advantages of spectral accuracy and block diagonal mass matrix. Numerical simulations are conducted to demonstrate the accuracy of the proposed method. Moreover, with an external DC magnetic field, HPM breakdown can be effectively delayed by increasing its breakdown threshold. Simultaneously, the phase shift of electromagnetic waves during the HPM breakdown can also be controlled by the external DC magnetic field, which can improve the quality of the phase-modulated signal in HPM illumination. This proposed framework is expected to provide an effective numerical tool for analyzing the microwave propagation characteristics and suppressing the HPM breakdown in gas-filled microwave devices.
3D characterization of individual grains of coexisting high-pressure H2O ice phases by time-domain Brillouin scattering
Authors: Sandeep Sathyan , Thréard Théo , De Lima Savi Elton , Chigarev Nikolay , Bulou Alain , Tournat Vincent , Zerr Andreas , Gusev Vitalyi E. , Raetz Samuel
Published: August 2021

Time-domain Brillouin scattering (TDBS) uses ultrashort laser pulses to (i) generate coherent acoustic pulses of picoseconds duration in a solid sample and (ii) follow their propagation in order to image material inhomogeneities with the axial resolution that can be deeply sub-optical, to nm-scale, and the lateral one down to the optical diffraction limit (half the optical wavelength of the probe laser). TDBS permits highly resolved 3D-imaging of grains in polycrystalline transparent samples with unlimited lateral sizes and thicknesses of at least 10 μm also when samples are orientationally textured and/or located in devices permitting access along one direction and from one side only. This optical technique presents, accordingly, clear advantages compared to any x-ray based computed tomography (neither back-projection algorithm nor multiple viewpoints of the sample are needed) and classical spectroscopic methods. Here, we applied TDBS to the 3D-imaging of a sample of polycrystalline water ice containing two high-pressure phases. The imaging, accomplished via a simultaneous detection of quasi-longitudinal and quasi-shear waves, provided shape, coordinates, phase content, and crystallographic orientation of resolved crystallites in a common coordinate system. Monitoring of acoustic pulses simultaneously propagating in two neighboring grains provided a new tool for the localization of grain boundaries.
A close look at the conformational transitions of a helical polymer in its response to environmental stimuli
Authors: Zhang Shuangshuang , Yuan Ning , Li Weiping , Wang Cuifang , Li Fuxin , Xu Jian , Suo Tongchuan
Published: August 2021

We present a study of the conformational transitions of a helical polymer by using coarse-grained molecular dynamics simulations. With focus on the variation of the dihedral angles, we are able to obtain the monomer-level details of the response of the polymer chain to environmental stimuli (e.g., temperature variation and mechanical forces). Specifically, during the thermo-induced helix–coil transition, all the helices break synchronously. On the contrary, the force-induced helix breaking always starts from the termini, and then the chain behaviors become divergent and temperature dependent. Particularly, at intermediate temperatures, we find that our polymer chain can adopt an asymmetrical half-trans conformation during the stretching procedures, although the chain itself has quite uniform and homogeneous composition.
A flexible and scalable, fully software-based lock-in amplifier for nonlinear spectroscopy
Authors: Uhl D. , Bruder L. , Stienkemeier F.
Published: August 2021

We demonstrate a cost-effective, fully software-based lock-in amplifier (LIA) implemented on a commercial computer. The device is designed for application in nonlinear spectroscopy, such as transient absorption and coherent multidimensional spectroscopy, but may also be used in any other application. The performance of our device is compared to a state-of-the-art commercial LIA with nearly identical results for both devices. Advantages of our device over commercial hardwired electronic LIAs are the improved flexibility in the data analysis and the possibility of arbitrary up-scaling of the number of LIA channels.
Active topolectrical circuits
Authors: Kotwal Tejas , Moseley Fischer , Stegmaier Alexander , Imhof Stefan , Brand Hauke , Kießling Tobias , Thomale Ronny , Ronellenfitsch Henrik , Dunkel Jörn
Published: August 2021

Significance

Originally discovered in condensed-matter physics, topological protection has become a unifying paradigm for understanding robust localized wave propagation in electronic, optical, acoustic, and even geophysical systems. The excitation of topologically protected waves in passive matter typically requires external forcing in a specific frequency range. Here, we show both theoretically and experimentally that robust topological edge modes can be spontaneously self-excited in active systems made from internally powered subunits. Presenting different realizations of active nonlinear electronic circuits, we demonstrate the emergence of self-organized topological wave patterns, in close agreement with predictions from a generic mathematical model. More broadly, these results can provide guidance for designing autonomous active systems with topologically protected signaling and transmission properties.
The muscle M3 x-ray diffraction peak and sarcomere length: No evidence for disordered myosin heads out of actin overlap
Authors: Squire John M. , Knupp Carlo
Published: August 2021

X-ray diffraction studies of muscle have provided a wealth of information on muscle structure and physiology, and the meridian of the diffraction pattern is particularly informative. Reconditi et al. (2014. J. Physiol.https://doi.org/10.1113/jphysiol.2013.267849) performed superb experiments on changes to the M3 meridional peak as a function of sarcomere length (SL). They found that the M3 intensity dropped almost linearly as sarcomere length increased at least to about SL = 3.0 µm, and that it followed the same track as tension, pointing toward zero at the end of overlap at ∼3.6 µm. They concluded that, just as tension could only be generated by overlapped myosin heads, so ordered myosin heads contributing to the M3 intensity could only occur in the overlap region of the A-band, and that nonoverlapped heads must be highly disordered. Here we show that this conclusion is not consistent with x-ray diffraction theory; it would not explain their observations. We discuss one possible reason for the change in M3 intensity with increasing sarcomere length in terms of increasing axial misalignment of the myosin filaments that at longer sarcomere lengths is limited by the elastic stretching of the M-band and titin.
The stability of Cl-, Br-, and I-passivated Si(100)-(2 × 1) in ambient environments for atomically-precise pattern preservation
Authors: Frederick E , Dwyer K J , Wang G T , Misra S , Butera R E
Published: August 2021

Atomic precision advanced manufacturing (APAM) leverages the highly reactive nature of Si dangling bonds relative to H- or Cl-passivated Si to selectively adsorb precursor molecules into lithographically defined areas with sub-nanometer resolution. Due to the high reactivity of dangling bonds, this process is confined to ultra-high vacuum (UHV) environments, which currently limits its commercialization and broad-based appeal. In this work, we explore the use of halogen adatoms to preserve APAM-derived lithographic patterns outside of UHV to enable facile transfer into real-world commercial processes. Specifically, we examine the stability of H-, Cl-, Br-, and I-passivated Si(100) in inert N2 and ambient environments. Characterization with scanning tunneling microscopy and x-ray photoelectron spectroscopy (XPS) confirmed that each of the fully passivated surfaces were resistant to oxidation in 1 atm of N2 for up to 44 h. Varying levels of surface degradation and contamination were observed upon exposure to the laboratory ambient environment. Characterization by ex situ XPS after ambient exposures ranging from 15 min to 8 h indicated the Br– and I–passivated Si surfaces were highly resistant to degradation, while Cl–passivated Si showed signs of oxidation within minutes of ambient exposure. As a proof-of-principle demonstration of pattern preservation, a H–passivated Si sample patterned and passivated with independent Cl, Br, I, and bare Si regions was shown to maintain its integrity in all but the bare Si region post-exposure to an N2 environment. The successful demonstration of the preservation of APAM patterns outside of UHV environments opens new possibilities for transporting atomically-precise devices outside of UHV for integrating with non-UHV processes, such as other chemistries and commercial semiconductor device processes.