bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility of Using Low-Cost Dual-Frequency GNSS Receivers for Land Surveying
Authors: Wielgocka Natalia , Hadas Tomasz , Kaczmarek Adrian , Marut Grzegorz
Published: March 2021

Global Navigation Satellite Systems (GNSS) have revolutionized land surveying, by determining position coordinates with centimeter-level accuracy in real-time or up to sub-millimeter accuracy in post-processing solutions. Although low-cost single-frequency receivers do not meet the accuracy requirements of many surveying applications, multi-frequency hardware is expected to overcome the major issues. Therefore, this paper is aimed at investigating the performance of a u-blox ZED-F9P receiver, connected to a u-blox ANN-MB-00-00 antenna, during multiple field experiments. Satisfactory signal acquisition was noticed but it resulted as >7 dB Hz weaker than with a geodetic-grade receiver, especially for low-elevation mask signals. In the static mode, the ambiguity fixing rate reaches 80%, and a horizontal accuracy of few centimeters was achieved during an hour-long session. Similar accuracy was achieved with the Precise Point Positioning (PPP) if a session is extended to at least 2.5 h. Real-Time Kinematic (RTK) and Network RTK measurements achieved a horizontal accuracy better than 5 cm and a sub-decimeter vertical accuracy. If a base station constituted by a low-cost receiver is used, the horizontal accuracy degrades by a factor of two and such a setup may lead to an inaccurate height determination under dynamic surveying conditions, e.g., rotating antenna of the mobile receiver.
Synthesis of Cu2O-Modified Reduced Graphene Oxide for NO2 Sensors
Authors: Huang Manman , Wang Yanyan , Ying Shuyang , Wu Zhekun , Liu Weixiao , Chen Da , Peng Changsi
Published: March 2021

Nowadays, metal oxide semiconductors (MOS)-reduced graphene oxide (rGO) nanocomposites have attracted significant research attention for gas sensing applications. Herein, a novel composite material is synthesized by combining two p-type semiconductors, i.e., Cu2O and rGO, and a p-p-type gas sensor is assembled for NO2 detection. Briefly, polypyrrole-coated cuprous oxide nanowires (PPy/Cu2O) are prepared via hydrothermal method and combined with graphene oxide (GO). Then, the nanocomposite (rGO/PPy/Cu2O) is obtained by using high-temperature thermal reduction under Ar atmosphere. The results reveal that the as-prepared rGO/PPy/Cu2O nanocomposite exhibits a maximum NO2 response of 42.5% and is capable of detecting NO2 at a low concentration of 200 ppb. Overall, the as-prepared rGO/PPy/Cu2O nanocomposite demonstrates excellent sensitivity, reversibility, repeatability, and selectivity for NO2 sensing applications.
Recognition of Cosmic Ray Images Obtained from CMOS Sensors Used in Mobile Phones by Approximation of Uncertain Class Assignment with Deep Convolutional Neural Network
Authors: Hachaj Tomasz , Bibrzycki Łukasz , Piekarczyk Marcin
Published: March 2021

In this paper, we describe the convolutional neural network (CNN)-based approach to the problems of categorization and artefact reduction of cosmic ray images obtained from CMOS sensors used in mobile phones. As artefacts, we understand all images that cannot be attributed to particles’ passage through sensor but rather result from the deficiencies of the registration procedure. The proposed deep neural network is composed of a pretrained CNN and neural-network-based approximator, which models the uncertainty of image class assignment. The network was trained using a transfer learning approach with a mean squared error loss function. We evaluated our approach on a data set containing 2350 images labelled by five judges. The most accurate results were obtained using the VGG16 CNN architecture; the recognition rate (RR) was 85.79% ± 2.24% with a mean squared error (MSE) of 0.03 ± 0.00. After applying the proposed threshold scheme to eliminate less probable class assignments, we obtained a RR of 96.95% ± 1.38% for a threshold of 0.9, which left about 62.60% ± 2.88% of the overall data. Importantly, the research and results presented in this paper are part of the pioneering field of the application of citizen science in the recognition of cosmic rays and, to the best of our knowledge, this analysis is performed on the largest freely available cosmic ray hit dataset.
Effect of Different Surface Designs on the Rotational Resistance and Stability of Orthodontic Miniscrews: A Three-Dimensional Finite Element Study
Authors: Choi Jin-Young , Cho Jaehee , Oh Song Hee , Kim Seong-Hun , Chung Kyu-Rhim , Nelson Gerald
Published: March 2021

High orthodontic forces and various directions of applied forces can be associated with loosening of the screw anchorage in the bone. Screw designs have been modified to increase the stability of the miniscrews. This research evaluates the influence of three-designs on the stability of orthodontic miniscrews. A conventionally cylinder-type miniscrew design (Bio-Action screw, Jin-Biomed co., Bucheon, Korea) was set as a control, and three conditions were studied based on modifications of this control design. Condition-1 has narrowed threads in the upper part of the screw; Condition-2 has a notch at the middle part; and Condition-3 has the combination of Condition-1 and Condition-2. The moment required to unwind the miniscrew to five degrees is tested, and the moment generated at the cortical bone and the trabecular bone were calculated with finite element analysis. Compared to the control, all three conditions showed a higher moment required to unwind the miniscrew and a higher moment generated at the cortical bone. At the trabecular bone, condition-2 and -3 showed higher moment than the control, and condition-1 showed similar moment to the control. Condition-3 required a higher overall moment to unwind the miniscrew. These findings validate the design modifications used to increase the rotational resistance.
Accurate Correlation Modeling between Wind Speed and Bridge Girder Displacement Based on a Multi-Rate Fusion Method
Authors: Wang Yan , Yang Dong-Hui , Yi Ting-Hua
Published: March 2021

Wind action is one of the environmental actions that has significant static and dynamic effects on long-span bridges. The lateral wind speed is the main factor affecting the lateral displacement of the main girder of the bridge. The main objective of the paper is to use the improved multi-rate fusion method to correct the monitoring data so that accurate correlation modeling of wind speed-displacement can be achieved. Two Kalman gain coefficients are introduced to improve the traditional multi-rate fusion method. The fusion method is verified by the results of simulated data analysis in time domain and frequency domain. Then, the improved multi-rate fusion method is used to fuse the monitoring lateral displacement and acceleration data of a bridge under strong wind action. The corrected lateral wind speed and displacement data is further applied to establish the correlation model through the linear regression. The improved multi-rate fusion method can overcome the inaccuracy of the high frequency stage of a Global Positioning System (GPS) sensor and the low frequency stage of acceleration sensor. The correlation coefficient of wind speed-displacement after fusion increases and the confidence interval width of regression model decreases, which indicates that the accuracy of the correlation model between wind speed and displacement is improved.
Adjustable Compliance Soft Sensor via an Elastically Inflatable Fluidic Dome
Authors: Zhang Xingtian , Kow Jun , Jones Dominic , de Boer Greg , Ghanbari Ali , Serjouei Ahmad , Culmer Pete , Alazmani Ali
Published: March 2021

Soft sensors are essential for robotic systems to safely interact with humans and the environment. Although significant research has been carried out in the field of soft tactile sensing, most of these sensors are restricted to a predefined geometry and a fixed measurement range, hence limiting their application. This paper introduces a novel approach to soft sensing by proposing a soft load-sensing unit with an adjustable mechanical compliance achieved using an elastically inflatable fluidic dome. The sensor consists of a three-dimensional Hall-effect sensor, above which is a magnet whose movement is modulated by an intermediate elastomeric dome structure. Sensor configurations were designed and fabricated using three different silicone rubbers to cover ‘00–10’ and ‘20A’ durometer shore hardness scales. We demonstrated that the compliance of the sensor could be dynamically tuned by changing the internal pressure of the inflatable fluidic dome in all configurations. We performed finite element simulations to determine the reaction force of the sensor under load as well as the stresses within the internal structural behavior, which are not possible to capture experimentally. The proposed soft sensor has the potential to be readily adapted for use in various soft robotic applications of differing size, compliance range, and safety requirements.
Relationship between Personality and Learning Goal Orientation Preceding the First Employment
Authors: Longin Maja Daraboš , Hruška Domagoj , Sedinić Vedrana
Published: March 2021

The purpose of this study is to explore the relation between personality traits and the level of aspiration to acquire new skills and improve one’s competence in the midst of first employment. Although with mixed results, previous studies indicated that personality attributes influence goal orientation, both in the school and work settings. However, there have not been any studies that have specifically analysed this relation in the context preceding the first employment. The results of this research, on a sample of last-semester business administration students of an esteemed mid-European university, indicate that prior to the first employment, two personality traits—openness to new ideas and disposition to negative emotions—influence the level of motivation to acquire knowledge and novel modes of action. Insight into the antecedents of an individual’s orientation towards increasing and developing competencies prior to the first employment is an important topic for organizations who have the imperative to develop more sustainable knowledge management practices in an early stage of organizational socialization.
Performance Shortfalls and R&D Investment Change: Aspirations, Actions, and Expectations
Authors: Huang Liying , He Lerong , Yang Guangqing
Published: March 2021

Built on the Behavioral Theory of the Firm, the paper examines how firm response to performance feedback is influenced by firm expectation on the likelihood of an action to close the performance gap. Using firm level change in R&D intensity as a problemistic search behavior, we explore how performance shortfalls relative to social and historical aspirations may prompt underperforming firms to adjust its R&D investment intensity, and how the magnitude of this adjustment is moderated by firm resources, past experience, industry and market conditions. We conduct our analysis using a longitudinal sample of Chinese firms listed on the ChiNext Board between 2009 and 2017. Our results indicate that underperforming firms increase their R&D intensity to a larger degree than their over-performing peers and periods when these firms have substantial cumulated R&D spending, abundant organizational slack, and are competing in more dynamic industries. We also document that these moderating factors influence relationships between social and historical aspirations and R&D investment decisions in a distinct way. We conclude that firm internal resources, capabilities and external industry and market conditions all affect firm expectations, and consequently shape the direction and magnitude of organizational actions in response to performance aspirations.
Autonomous Vehicle Use and Urban Space Transformation: A Scenario Building and Analysing Method
Authors: Silva Dahlen , Földes Dávid , Csiszár Csaba
Published: March 2021

The use of autonomous vehicles (AVs) has the potential to transform users’ behaviour and urban space management. Quantitative and qualitative analyses of impacts require a scenario building method. We considered the fleet size, modal share, car ownership, parking preferences, and urban space repurposing during the elaboration of a novel method. Existing scenarios and results of a questionnaire survey have been used as sources. The method was applied to build scenarios in a case study in Budapest, Hungary. The results were used to calculate the impacts on urban space management, including environmental savings. The key findings are: scenarios with significant shared AV use show that parking demand may be minimised (almost 83%) and urban space repurposing has the highest potential; furthermore, AV use and sharing acceptability may decrease the fleet size and alter the type of shared mode to multiple occupancies. The developed scenario building method serves as a base for future studies. The produced scenarios allow the researchers to focus on the analysis of the impacts caused.
How Regional Trust Cues Could Drive Decentralisation in the Energy Sector—An Exploratory Approach
Authors: Menzel Tobias , Teubner Timm
Published: March 2021

The Green Information Systems research stream was initiated by leading information systems researchers to address climate change through information and communications technology. This paper responds to a call for practical research into the design of information systems that support consumers in their decision making in favour of sustainable products. We apply an exploratory approach to improve understanding of regional trust cues in the energy sector and how these could drive the sector’s decentralisation. We explore the still emerging phenomenon of regional text and imagery on digital user interfaces via a multi-method process including quantitative and qualitative content analysis. Our findings suggest that regional energy providers systematically employ regional textual and pictorial trust cues on their websites. We further lay the ground for future experimental work on this matter by defining terms and concepts and systematically capturing design elements. We outline practical implications for designing user interfaces in the energy sector and discuss how this could drive the sector’s platformisation and sustainabilisation. In addition, we discuss implications for consumers who could become the target of regional washing attempts, in other words providers applying regional cues to create a regional company image in the absence of actual regionality.
Nature-Based Solutions—Concept, Evaluation, and Governance
Authors: Lupp Gerd , Zingraff-Hamed Aude
Published: March 2021

Climate change results in an increase of the frequency and intensity of extreme hydro-meteorological risks such as floods, mudflows, landslides, avalanches and rockfalls jeopardizing a great number of people, settlements and critical infrastructures every year [...]
How Will the Technological Shift in Transportation Impact Cities? A Review of Quantitative Studies on the Impacts of New Transportation Technologies
Authors: Maheshwari Tanvi , Axhausen Kay W.
Published: March 2021

Recent developments in vehicle automation, connectivity, electro-mobility and ridesharing are expected to transform urban mobility patterns and reshape cities. There is enormous uncertainty about how these technological developments, collectively referred to as the ‘technological shift in transportation’, may impact cities. This paper examines whether the technological shift in transportation will lead cities on a path to sustainability in five aspects—traffic flow, space use, energy consumption, transit and active mobility and economic affordability—through a review of 34 quantitative studies. We find that these studies backed by analytical and simulation models can provide more precise answers, and their results tend to contradict each other based on starting conditions, modelling methods and other driving factors. These driving factors fall within four categories: technological integration, policy, operations and urban planning. The interaction of these driving forces will determine if the technological shift improves transportation sustainability or is detrimental for the city in the long term.
The Role of the External Accountant in Business Planning for Starters: Perspective of the Self-Determination Theory
Authors: De Bruyckere Stefanie , Everaert Patricia
Published: March 2021

The objective of this study was to gain more insight into the value of business planning for starters and to better understand the role of the external accountant in the planning stage. In particular, survey research was conducted to capture both the quality of the business plan and its effectiveness as perceived by the starter. To unravel the underlying reasons behind the development of a business plan, the framework of the self-determination theory (SDT) was used and adapted to this context. SDT proposes a continuum that distinguishes four types of motivation, ranging from external motivation (i.e., developing a business plan because of a legal obligation) to intrinsic motivation (i.e., developing a business plan because of a personal interest). The results, based on 283 surveys of Belgian starters, showed a relationship between the type of motivation and the quality of the business plan. Entrepreneurs with high introjected or high identified motivation seem to develop a high-quality business plan. This high-quality business plan enables entrepreneurs to increase their effectiveness. Furthermore, entrepreneurs who consulted an accountant during the business planning stage perceived the quality of their business plan as higher than entrepreneurs who did not get advice from an accountant. These findings presuppose an important challenge for external accountants, as their business advice supports entrepreneurs in anticipating “the unexpected”, which subsequently empowers them to monitor their business effectively.
Stabilization of a Clay Soil Using Cementing Material from Spent Refractories and Ground-Granulated Blast Furnace Slag
Authors: Seco Andres , del Castillo Jesus María , Espuelas Sandra , Marcelino-Sadaba Sara , Garcia Benat
Published: March 2021

Nowadays, huge amounts of refractory materials are generated around the world. The majority of them lack valorization methods. This study analyzes the ability of a doloma and two magnesia spent refractory wastes as soil stabilizers on their own, as well as when combined with Ground-Granulated Blast Furnace Slags (GGBS). These materials showed a limited ability for the soil’s plasticity modification from a plasticity index of 15.6 to a minimum of 12.7. The high pH of the additives increased the soil’s pH from 7.88 to values in the range of 10.94–11.25 before the 28 days, allowing the development of the pozzolanic reactions. Unconfined compressive strength (UCS) increased along the curing time, reaching a maximum value of 5.68 MPa after 90 days. Based on the UCS, the optimum refractory GGBS ratios oscillate between 30:70 and 50:50. The UCS values after soaking samples reduced the unsoaked results between 68.70% to 94.41%. The binders considered showed a low effect against the soil swelling and the lack of delayed expansive effects because of the MgO hydration. Finally, X Ray Diffraction (XRD) tests showed that the stabilization only slightly modified the combinations of mineralogy and the formation of Magnesium Silicate Hydrate (MSH) gels.
Heat and Fluid Flow Analysis and ANN-Based Prediction of A Novel Spring Corrugated Tape
Authors: Souayeh Basma , Bhattacharyya Suvanjan , Hdhiri Najib , Waqas Alam Mir
Published: March 2021

A circular tube fitted with novel corrugated spring tape inserts has been investigated. Air was used as the working fluid. A thorough literature review has been done and this geometry has not been studied previously, neither experimentally nor theoretically. A novel experimental investigation of this enhanced geometry can, therefore, be treated as a new substantial contribution in the open literature. Three different spring ratio and depth ratio has been used in this study. Increase in thermal energy transport coefficient is noticed with increase in depth ratio. Corrugated spring tape shows promising results towards heat transfer enhancement. This geometry performs significantly better (60% to 75% increase in heat duty at constant pumping power and 20% to 31% reduction in pumping power at constant heat duty) than simple spring tape. This paper also presented a statistical analysis of the heat transfer and fluid flow by developing an artificial neural network (ANN)-based machine learning (ML) model. The model is evaluated to have an accuracy of 98.00% on unknown test data. These models will help the researchers working in heat transfer enhancement-based experiments to understand and predict the output. As a result, the time and cost of the experiments will reduce. The results of this investigation can be used in designing heat exchangers.
Platforms Enhancing the Engagement of the Private Sector in Humanitarian Relief Operations
Authors: Cozzolino Alessandra
Published: March 2021

As disasters become progressively more frequent and complex, better collaboration through partnerships with private business becomes more important. This research aimed to understand how platforms support the engagement of the private sector—especially logistics businesses—in humanitarian relief operations. The study was based on a literature review and on an investigation of an emblematic case of the cross-sector platform, recognized at a global level in logistics and supply chain management, between the United Nations World Food Programme and the Logistics Emergency Teams (WFP/LET), composed of four global leading logistics providers. The insights resulting from this paper may be of particular interest to both academics and professionals regarding the two sectors, profit and non-profit. This is because the implementation of the platform reflects the concrete benefit for people in need reached by the humanitarian relief operations. It may also constitute a useful tool for building an agile supply chain capable of being resilient in responding to sudden and unexpected changes in the context, both in humanitarian and commercial supply chains.
Sustainable Applications of Smart-Government Services: A Model to Understand Smart-Government Adoption
Authors: Althunibat Ahmad , Binsawad Muhammad , Almaiah Mohammed Amin , Almomani Omar , Alsaaidah Adeeb , Al-Rahmi Waleed , Seliaman Mohamed Elhassan
Published: March 2021

Despite the fact that several studies have been conducted to study the adoption of smart-government services, little consideration has been paid to exploring the main factors that influence the adoption of smart-government services at the three main stages of smart-government services (the static, interaction, and transaction stages). Based on the results of this study, each of these three stages has different requirements in terms of system compatibility, security, information quality, awareness, perceived functional benefit, self-efficacy, perceived image, perceived uncertainty, availability of resources, and perceived trust. In addition, the results demonstrate that the requirements and perceptions of users towards the adoption and use of smart-government services in the three stages significantly differ. This study makes a unique contribution to the existing research by examining the perceptions and needs of consumers, in terms of adoption throughout the three stages.
Factors Affecting COVID-19 Outbreaks across the Globe: Role of Extreme Climate Change
Authors: Nath Debashis , Sasikumar Keerthi , Nath Reshmita , Chen Wen
Published: March 2021

The Coronavirus Disease 2019 (COVID-19) pandemic poses a serious threat to global health system and economy. It was first reported in Wuhan, China, and later appeared in Central Asia, Europe, North America, and South America. The spatial COVID-19 distribution pattern highly resembles the global population distribution and international travel routes. We select 48 cities in 16 countries across 4 continents having infection counts higher than 10,000 (by 25 April 2020) as the COVID-19 epicenters. At the initial stage, daily COVID-19 counts co-varies strongly with local temperature and humidity, which are clustered within 0–10 °C and 70–95%, respectively. Later, it spreads in colder (−15 °C) and warmer (25 °C) countries, due to faster adaptability in diverse environmental conditions. We introduce a combined temperature-humidity profile, which is essential for prediction of COVID-19 cases based on environmental conditions. The COVID-19 epicenters are collocated on global CO2 emission hotspots and its distribution maximizes at 7.49 °C, which is 1.35 °C/2.44 °C higher than current (2020)/historical (1961–1990) mean. Approximately 75% of the COVID-19 cases are clustered at severe-extreme end of historical temperature distribution spectrum, which establish its tighter and possible association with extreme climate change. A strong mitigation measure is essential to abate the GHG emissions, which may reduce the probability of such pandemics in the future.
Characterization of Technological Innovations in Photovoltaic Rural Electrification, Based on the Experiences of Bolivia, Peru, and Argentina: Third Generation Solar Home Systems
Authors: Fernandez-Fuentes Miguel H. , Eras-Almeida Andrea A. , Egido-Aguilera Miguel A.
Published: March 2021

The electrification of isolated homes in rural areas without access to the electric grid has been achieved in part using solar energy transformed into electricity through Photovoltaic (PV) equipment known as Solar Home Systems (SHSs), which has been widely disseminated throughout the world. The use of SHSs in rural electrification projects has been studied from 1980 to date, they have been incorporating advances and technological innovations successively. Through the review of documents on PV projects, articles, and technical reports, it has been possible to identify the changes in the main components of the SHS and the typical configurations, systematizing them in a discrete timeline. Thereby, this article characterizes three generations of SHSs and highlights their differences. The first generation is fully valid between 1980–1995, the second generation in 1995–2010, and the third generation from 2005 to date, which overlaps the beginning. In any case, the time limits in each period are only referential. The later generation, Third Generation Solar Home Systems (3G-SHSs), is highly efficient, uses LED lamps, lithium batteries, microelectronic control, and plug and play connections. Indeed, this equipment can be self-managed by the user and reflects the technology’s high reliability by a minimum maintenance service in situ. Furthermore, their lower costs make access to electricity more affordable for the last mile population. The present research offers a detailed technological and operational characterization of the 3G-SHSs to show the most relevant aspects of support to project developers, planners, and decision-makers to achieve the Sustainable Development Goal (SDG) 7.
Classification of TOD Typologies Based on Pedestrian Behavior for Sustainable and Active Urban Growth in Seoul
Authors: Woo Jung Hyun
Published: March 2021

Transit-oriented development (TOD) pursues sustainable urban development through compact growth, mixed-use zoning, and pedestrian-friendly neighborhood design in cooperation with transportation planning. Seoul has actively developed urban rail transit since the 1970s based on a TOD concept, and each station’s areas have differently evolved throughout the history of urbanization in Seoul. In response to investigating the complications of current TOD, this paper evaluates TOD characteristics through accessibility and clustering analysis methods and categorizes TOD types using the targeted 246 subway station areas at the neighborhood level. As a result, subway TODs are grouped into the four distinct categories of (1) high-density: a form of mainly mixed-use with residential and retail development and good accessibility; (2) moderate-density: average accessibility and high-mixed use; (3) compact business district setting: highly accessible to offices and retail; and (4) compact housing: high-rise apartments with schools and retail. The results also find that Cluster 2 is the most common TOD type and redevelopment possibility in Seoul, with relatively lower ranks in the building floor area (GFA) and diversity in comparison to other TOD contexts. Cluster 3 has the most significant transit demand, generating an active transit environment in Seoul. Different urban development periods impact the characteristics of TOD types.
Using Combined Bus Rapid Transit and Buses in a Dedicated Bus Lane to Enhance Urban Transportation Sustainability
Authors: Hoonsiri Chinnawat , Chiarakorn Siriluk , Kiattikomol Vasin
Published: March 2021

Combined bus rapid transit and buses in a dedicated bus lane (CBBD) is a measure that bus rapid transit (BRT) operators implement to reduce overlapping routes between BRT and fixed-route buses. The CBBD measure can combine the passengers of both systems on the same route, which helps increase passenger demand for the BRT, and reduce fuel consumption and emissions from utilizing the exclusive lanes for the combined route. However, the CBBD could affect some bus and BRT passengers in terms of either losing or gaining travel time-saving benefits depending on their travel pattern. This research proposed a methodology to determine the travel distance initiating disadvantage for BRT passengers (DDB) to justify the potential success of the CBBD operations. The number of passengers gaining a benefit from the CBBD was sensitive to the distance between the CBBD stops and the operational period of the CBBD. The CBBD reform would be beneficial to transit agencies to improve the travel time of passengers and be able to promote environmental sustainability for the public transportation system in urban cities.
Study on Migratory Behavior of Aggregate in Asphalt Mixture Based on the Intelligent Acquisition System of Aggregate Attitude Data
Authors: Zhang Chen , Zhang Zhengwei
Published: March 2021

In order to provide a new method to study the migration behavior of coarse aggregates in the compaction process of asphalt mixtures, the “Intelligent Aggregate Attitude Acquisition System (IAS)” is developed based on 3D printing technology and wireless intelligent sensing technology, and the “Intelligent Attitude Aggregate (IAA)” is prepared as the acquisition terminal. The Superpave Gyratory Compaction (SGC) test and the Internet of Things (IOT) wireless sensor technology are combined to collect and analyze the attitude data of an SMA-20 asphalt mixture built in IAA at different compaction stages, and the migration behavior of coarse aggregate in the compaction process is quantitatively characterized. The result shows that the IAA is suitable as a “tracking aggregate” to study the aggregate transfer behavior in asphalt mixtures. The IAA in the upper layer tends to move vertically downward, while the particles in the lower layer tend to move horizontally and spatial rotation in the process of rotating compaction. With the increase in asphalt content, the lubrication effect between aggregate particles is obvious, and the friction resistance of aggregate particles decreases when it is embedded downward. Affected by shear force in the process of rotary compaction, the aggregate particles are easier to overcome friction and cause large horizontal migration and spatial rotation. With the increase in compaction temperature, the viscosity of asphalt binder decreases, and the contact friction between aggregate particles decreases. The asphalt content has a significant effect on the displacement in the horizontal plane Dxoy of the aggregate. The asphalt content and compaction temperature have significant effects on the spatial rotation angle Φ of aggregate, but the asphalt content has a greater impact on it.
Comfort within Budget: Assessing the Cost-Effectiveness of Envelope Improvements in Single-Family Affordable Housing
Authors: Tubelo Renata , Rodrigues Lucelia , Gillott Mark , Zune May
Published: March 2021

In Brazil, the delivery of homes for low-inc ome households is dictated by costs rather than performance. Issues such as the impact of climate change, affordability of operational energy use, and lack of energy security are not taken into account, even though they can severely impact the occupants. In this work, the authors evaluated the thermal performance of two affordable houses as-built and after the integration of envelope improvements. A new replicable method to evaluate the cost-effectiveness of these improvements was proposed. The case study houses comprise the most common affordable housing type delivered widely across Brazil and a proposition of a better affordable housing solution, built in Porto Alegre, southern Brazil, integrating passive design strategies to increase thermal comfort. The findings reveal a potential for improving indoor thermal conditions by up to 76% and 73%, respectively, if costs are not a concern, and 40% and 45% with a cost increase of 12% and 9% if a comfort criterion of 20–25 °C was considered. Equations to estimate costs of improvements in affordable housing were developed. The authors concluded that there is a great scope for building envelope optimisation, and that this is still possible without significant impact on budget.
Student Development at the Boundaries: Makerspaces as Affordances for Engineering Students’ Development
Authors: Choi Yoon Ha , Bouwma-Gearhart Jana , Lenhart Cindy A. , Villanueva Idalis , Nadelson Louis S.
Published: March 2021

University-based makerspaces are receiving increasing attention as promising innovations that may contribute to the development of future engineers. Using a theory of social boundary spaces, we investigated whether the diverse experiences offered at university-based makerspaces may contribute to students’ learning and development of various “soft” or “21st century” skills that go beyond engineering-specific content knowledge. Through interviews with undergraduate student users at two university-based makerspaces in the United States we identified seven different types of boundary spaces (where multiple communities, and the individuals and activities affiliated with those communities, come together). We identified students engaging in the processes of identification, reflection, and coordination, which allowed them to make sense of, and navigate, the various boundary spaces they encountered in the makerspaces. These processes provided students with opportunities to engage with, and learn from, individuals and practices affiliated with various communities and disciplines. These opportunities can lead to students’ development of necessary skills to creatively and collaboratively address interdisciplinary socio-scientific problems. We suggest that university-based makerspaces can offer important developmental experiences for a diverse body of students that may be challenging for a single university department, program, or course to offer. Based on these findings, we recommend university programs and faculty intentionally integrate makerspace activities into undergraduate curricula to support students’ development of skills, knowledge, and practices relevant for engineering as well as 21st century skills more broadly.
A Global PSS Framework for Sustainable B2B Partnership
Authors: Graça Sandra S.
Published: March 2021

Committed Business-to-Business (B2B) relationships are linked to sustainable business partnerships and greater profitability. As competition increases, suppliers must seek to differentiate by shifting the focus of their offerings from the product to services that contribute to create additional value to buyers. This empirical research proposes a product-service system (PSS) framework within the context of a relationship marketing (RM) model tested across a sample of United States (US) and Brazilian buyers. The study examines the impact of value-added benefits on building sustainable B2B partnerships. Results demonstrate that a firm’s servitization strategy that delivers both functional and social benefits fosters greater information exchange and mutual cooperation, which in turn contributes to increase buyer’s trust in, satisfaction with and commitment to a supplier. Despite some noted differences found in the commitment-building process, results show the importance that additional services have on promoting long-term, sustainable B2B partnerships across countries in distinct stages of economic development.
A Comparative Analysis of Spatial Data and Land Use/Land Cover Classification in Urbanized Areas and Areas Subjected to Anthropogenic Pressure for the Example of Poland
Authors: Szarek-Iwaniuk Patrycja
Published: March 2021

Urbanization processes are some of the key drivers of spatial changes which shape and influence land use and land cover. The aim of sustainable land use policies is to preserve and manage existing resources for present and future generations. Increasing access to information about land use and land cover has led to the emergence of new sources of data and various classification systems for evaluating land use and spatial changes. A single globally recognized land use classification system has not been developed to date, and various sources of land-use/land-cover data exist around the world. As a result, data from different systems may be difficult to interpret and evaluate in comparative analyses. The aims of this study were to compare land-use/land-cover data and selected land use classification systems, and to determine the influence of selected classification systems and spatial datasets on analyses of land-use structure in the examined area. The results of the study provide information about the existing land-use/land-cover databases, revealing that spatial databases and land use and land cover classification systems contain many equivalent land-use types, but also differ in various respects, such as the level of detail, data validity, availability, number of land-use types, and the applied nomenclature.
Identifying High-Level Concept Clones in Software Programs Using Method’s Descriptive Documentation
Authors: Gupta Aditi , Goyal Rinkaj
Published: March 2021

Software clones are code fragments with similar or nearly similar functionality or structures. These clones are introduced in a project either accidentally or deliberately during software development or maintenance process. The presence of clones poses a significant threat to the maintenance of software systems and is on the top of the list of code smell types. Clones can be simple (fine-grained) or high-level (coarse-grained), depending on the chosen granularity of code for the clone detection. Simple clones are generally viewed at the lines/statements level, whereas high-level clones have granularity as a block, method, class, or file. High-level clones are said to be composed of multiple simple clones. This study aims to detect high-level conceptual code clones (having granularity as java methods) in java-based projects, which is extendable to the projects developed in other languages as well. Conceptual code clones are the ones implementing a similar higher-level abstraction such as an Abstract Data Type (ADT) list. Based on the assumption that “similar documentation implies similar methods”, the proposed mechanism uses “documentation” associated with methods to identify method-level concept clones. As complete documentation does not contribute to the method’s semantics, we extracted only the description part of the method’s documentation, which led to two benefits: increased efficiency and reduced text corpus size. Further, we used Latent Semantic Indexing (LSI) with different combinations of weight and similarity measures to identify similar descriptions in the text corpus. To show the efficacy of the proposed approach, we validated it using three java open source systems of sufficient length. The findings suggest that the proposed mechanism can detect methods implementing similar high-level concepts with improved recall values.
Recent Developments of the Lauricella String Scattering Amplitudes and Their Exact SL(K + 3,C) Symmetry
Authors: Lai Sheng-Hong , Lee Jen-Chi , Yang Yi
Published: March 2021

In this review, we propose a new perspective to demonstrate the Gross conjecture regarding the high-energy symmetry of string theory. We review the construction of the exact string scattering amplitudes (SSAs) of three tachyons and one arbitrary string state, or the Lauricella SSA (LSSA), in the 26D open bosonic string theory. These LSSAs form an infinite dimensional representation of the SL(K+3,C) group. Moreover, we show that the SL(K+3,C) group can be used to solve all the LSSAs and express them in terms of one amplitude. As an application in the hard scattering limit, the LSSA can be used to directly prove the Gross conjecture, which was previously corrected and proved by the method of the decoupling of zero norm states (ZNS). Finally, the exact LSSA can be used to rederive the recurrence relations of SSA in the Regge scattering limit with associated SL(5,C) symmetry and the extended recurrence relations (including the mass and spin dependent string BCJ relations) in the nonrelativistic scattering limit with the associated SL(4,C) symmetry discovered recently.
Contamination Assessment of Heavy Metals in Agricultural Soil, in the Liwa Area (UAE)
Authors: Al-Taani Ahmed A. , Nazzal Yousef , Howari Fares M. , Iqbal Jibran , Bou Orm Nadine , Xavier Cijo Madathil , Bărbulescu Alina , Sharma Manish , Dumitriu Cristian-Stefan
Published: March 2021

The Liwa area is a primary food production area in the United Arab Emirates (UAE) and has intensively been used for agriculture. This study investigates the pollution levels with heavy metals in agricultural soils from the Liwa area. Thirty-two soil samples were analyzed for Mn, Zn, Cr, Ni, Cu, Pb, Cd, Co, and As. Results revealed that heavy metal levels varied in the ranges 220.02–311.21, 42.39–66.92, 43.43–71.55, 32.86–52.12, 10.29–21.70, 2.83–8.84, 0.46–0.69, 0.03–0.37 mg/kg for Mn, Zn, Cr, Ni, Cu, Pb, Cd, Co, and As, respectively. All samples presented low As concentrations with an average of 0.01 mg/kg. The variations in bulk metal contents in the soil samples were related to multiple sources, including agrochemicals, atmospheric dust containing heavy metals, and traffic-related metals. Enrichment factor analysis indicates that Cd, Ni, Zn, and Cr were highly enriched in soils, and they could originate from non-crustal sources. Based on the geo-accumulation index (Igeo), the soil samples appeared uncontaminated with Mn, Cr, Zn, Pb, Co, As, Cu, uncontaminated to moderately contaminated with Ni and moderately contaminated with Cd. The contamination factors suggest low contamination, except for Ni, which showed moderate contamination. The average pollution load index (PLI) revealed unpolluted to low pollution of all soil samples. The ecological risk assessment (PERI) showed that all heavy metals posed a low risk, except for Cd which exhibited a high ecological risk.
Zearalenone Induces Apoptosis and Cytoprotective Autophagy in Chicken Granulosa Cells by PI3K-AKT-mTOR and MAPK Signaling Pathways
Authors: Zhu Yifeng , Wang Heng , Wang Jianping , Han Shunshun , Zhang Yao , Ma Menggen , Zhu Qing , Zhang Keying , Yin Huadong
Published: March 2021

Zearalenone (ZEA) is a nonsteroidal estrogenic mycotoxin found in several food commodities worldwide. ZEA causes reproductive disorders, genotoxicity, and testicular toxicity in animals. However, little is known about the functions of apoptosis and autophagy after exposure to ZEA in granulosa cells. This study investigated the effects of ZEA on chicken granulosa cells. The results show that ZEA at different doses significantly inhibited the growth of chicken granulosa cells by inducing apoptosis. ZEA treatment up-regulated Bax and downregulated Bcl-2 expression, promoted cytochrome c release into the cytosol, and triggered mitochondria-mediated apoptosis. Consequently, caspase-9 and downstream effector caspase-3 were activated, resulting in chicken granulosa cells apoptosis. ZEA treatment also upregulated LC3-II and Beclin-1 expression, suggesting that ZEA induced a high level of autophagy. Pretreatment with chloroquine (an autophagy inhibitor) and rapamycin (an autophagy inducer) increased and decreased the rate of apoptosis, respectively, in contrast with other ZEA-treated groups. Autophagy delayed apoptosis in the ZEA-treated cells. Therefore, autophagy may prevent cells from undergoing apoptosis by reducing ZEA-induced cytotoxicity. In addition, our results further show that the autophagy was stimulated by ZEA through PI3K-AKT-mTOR and MAPK signaling pathways in chicken granulosa cells.
Nonperturbative Quantization Approach for QED on the Hopf Bundle
Authors: Dzhunushaliev Vladimir , Folomeev Vladimir
Published: March 2021

We consider the Dirac equation and Maxwell’s electrodynamics in R×S3 spacetime, where a three-dimensional sphere is the Hopf bundle S3→S2. In both cases, discrete spectra of classical solutions are obtained. Based on the solutions obtained, the quantization of free, noninteracting Dirac and Maxwell fields is carried out. The method of nonperturbative quantization of interacting Dirac and Maxwell fields is suggested. The corresponding operator equations and the infinite set of the Schwinger–Dyson equations for Green’s functions is written down. We write a simplified set of equations describing some physical situations to illustrate the suggested scheme of nonperturbative quantization. Additionally, we discuss the properties of quantum states and operators of interacting fields.
Charged Residues in the Membrane Anchor of the Pestiviral Erns Protein Are Important for Processing and Secretion of Erns and Recovery of Infectious Viruses
Authors: Oetter Kay-Marcus , Kühn Juliane , Meyers Gregor
Published: March 2021

The pestivirus envelope protein Erns is anchored in membranes via a long amphipathic helix. Despite the unusual membrane topology of the Erns membrane anchor, it is cleaved from the following glycoprotein E1 by cellular signal peptidase. This was proposed to be enabled by a salt bridge-stabilized hairpin structure (so-called charge zipper) formed by conserved charged residues in the membrane anchor. We show here that the exchange of one or several of these charged residues reduces processing at the Erns carboxy-terminus to a variable extend, but reciprocal mutations restoring the possibility to form salt bridges did not necessarily restore processing efficiency. When introduced into an Erns-only expression construct, these mutations enhanced the naturally occurring Erns secretion significantly, but again to varying extents that did not correlate with the number of possible salt bridges. Equivalent effects on both processing and secretion were also observed when the proteins were expressed in avian cells, which points at phylogenetic conservation of the underlying principles. In the viral genome, some of the mutations prevented recovery of infectious viruses or immediately (pseudo)reverted, while others were stable and neutral with regard to virus growth.