bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy savings in compressed air systems a case of study
Authors: Hernández Herrera H , Villalba D Patiño , Angarita E Noriega , Silva Ortega J I , Caraballo Echavarría C A 
Published: July 2021

Abstract
The compressed air applications are highly used in the industrial sector due to its easy transportation, safety, purity, cleanliness and storage capacity. In many regions, compressed air system accounts for about 10% of the industrial electricity energy bill. However, compressed air is expensive because around 30% of the consumed energy is used for these systems in an industrial facility. Energy used to be lost as leaks, pressure drops, heat, misuse, among others. Several energy efficiencies measures help to improve energy savings in companies such as: pressure reduction, reduce the inlet air temperature, use a well-calculated capacity tank for storage, control heat recovery and reduce leaks, giving potential energy savings in a range between the 20% to 60%, with a return of investment not higher than two years. As result, this document analyzes the energy efficiency measures that can be considered for compressed air systems applications, calculates the energy saving potentials, and assesses a case of study in a company in the city of Barranquilla.
The discharge and shell temperatures in hermetic compressors during its operation in tropical weather conditions
Authors: Arencibia Avila K.J. , Mendoza Fandiño J.M. , Cabello Eras J.J. , Sagastume Gutiérrez A. , Fernández Periche F. 
Published: July 2021

Abstract
Hermetic compressors are essential components of domestic refrigerators and freezers and are usually designed to operate in ambient temperatures under 32°C. This study measures the discharge and shell temperatures of hermetic compressors at different ambient temperatures. To this end, calorimetric tests are conducted in three different hermetic compressors to define the impact of tropical ambient temperatures on the discharge and shell temperatures. Environmental temperatures of 35, and 38°C and voltages of 93, 115, and 127 V were considered during the tests. Thi results are compared to the nominal parameters at 32°C and 115V. Furthermore, to identify if the wear-out of the different components affect the discharge and shell temperatures, the three compressors were tested in the calorimeter after an accelerated life test. In all cases, the evaporation temperature was controlled at -23 °C. Results show that the discharge and shell temperatures of hermetic compressors increase with the ambient temperature. Additionally, it is evidenced that the technology of hermetic compressors strongly influences the discharge and shell temperatures.
Artificial intelligence model for the prediction of malignant tumors using a set of medical images from mammography studies
Authors: Sánchez S A , Morales A D , Arroyo M F , Asís y H D 
Published: July 2021

Abstract
Currently, the diagnosis of tumors and malignant cells through imaging studies is a great challenge for expert medical personnel, due to the complexity of achieving an early prediction of cancer cells, which would allow to accelerate early medical treatments. Today, technologies have become a fundamental ally for the health sector, specifically the area of artificial intelligence, which has permeated many disciplines, generating important advances. Advances in parallel computing, GPU technology, and deep learning have made real-time image processing easier. The main objective of this research was to generate a deep learning model for the prediction of malignant cells in medical images of diagnosed mammograms. Using the previously trained model based on Faster R-CNN, with the ResNet function extractor. This model works in the Python programming language, using the Tensorflow framework and the OpenCv library. The algorithms were previously trained through the DDSM and MIAS open medical image databases, published on the web. This model not only focuses on recognizing and classifying malignant cells in the image, but also on the location of objects within it, appropriately drawing a bounding box. One of the latent challenges of these models since their inception has been the consumption of computing, but today they have been optimized so much that they allow freezing the pre-trained models by loading them in the memory of the devices, managing to use them in computers without GPUs. As a result, it was found that the Faster R-CNN method with the Resnet 101 extractor offers great advantages of precision and speed when it comes to detecting malignant tumors, studies that can serve as a great contribution to the bets of this algorithm in the health sector.
Designing a system with machine learning to formative research projects management
Authors: Pineda C. , Morales A. , Lopez L. , Benitez C. , Sanchez S. 
Published: July 2021

Abstract
Artificial intelligence is marked among emerging technologies and is one of the most projected expectations for future dates. In the last decade this technology has been implemented in various sectors, without leaving the education and research sector, generating positive results. Among the most demanded algorithms are machine learning, because it gives the ability to “learn” to machines and information systems through experience and not rely only on data from system inputs in a given context. For this reason and also because of the difficulty that students and teachers express in the elaboration of training research documents, the objective of this research is to design a system that assists the user in the construction of the different sections of a formative research project. The research is descriptive and technological development. Among the results found is the behavior of the proposed system and identifies the different technologies to be used for future development. It is concluded that the system is structured by the MVC(Model View-Controller) architectural pattern which facilitates the scalability and maintenance of the system in the future, in addition to the implementation of the libraries of Python, NLTK(Natural Language Toolkit), Scikit-learn, Tensor Flow and Keras, allow the system to fully use machine learning for scientific and academic text prediction.
Airfoil Shape Optimization: Comparative Study of Meta-heuristic Algorithms, Airfoil Parameterization Methods and Reynolds Number Impact
Authors: Hoyos JoséD , Jímenez Jesús H , Echavarría Camilo , Alvarado Juan P 
Published: July 2021

Abstract
The aerodynamic efficiency in airfoil theory is defined as the ratio between the lift and drag force, which is the main objective function to be maximized in a wide kind of vehicle design due to its strong relationship between fuel consumption and range. This work employs the 4-digits NACA parameterization, a recently developed 6-parameters method, and the PARSEC technique with a correction of the matrices available in the literature, to compare the computational cost and the ability to achieved higher efficiency of these parameterizations. A genetic algorithm and particle swarm optimization routines are developed and implemented in Matlab, also a sine-cosine algorithm is tested, where Xfoil and the open-source computational fluid dynamic software OpenFOAM are coupled with the optimization algorithms. Finally, a Reynolds number impact study is performed related to the airfoil shape and the angle of attack which maximizes the aerodynamic efficiency. The results showed a faster convergence for the particle swarm optimization and the highest aerodynamic efficiency achieved by the 6-parameter method. Furthermore, with a higher Reynolds number, a higher angle of attack for the optimum lift-to-drag ratio as well a less camber is obtained.
Exergetic Analysis of a Parabolic Trough Collector System Operating with Different Heat Transfer Fluids
Authors: Carrillo G E , Cárdenas Y 
Published: July 2021

Abstract
Solar concentrating systems are one of the most promising technologies to supply process heat or generate electricity. Responding to the global problem of increasing pollutants in the atmosphere and contributing to the diversification of the world’s energy matrix. In this sense, the Parabolic Trough Collector system represents the technology with the greatest technological maturity and hours of commercial operation. Thus, this paper presents an exergetic analysis of this type of system, based on the configuration of a system installed in the city of Itajuba-MG, Brazil. As a way to identify the improvement potentials of this type of system and thus obtain performance improvements. In the initial stage, the exergetic balance on the system’s receiver is developed. The effect of the loss of exergy and the destruction of exergy on the exergy of the fluid inside the receiver tube is determined. In the next stage, the required parameters were defined to calculate the terms defined in the first stage. Among these parameters is the effect of exergy of solar irradiation, heat losses, the optical efficiency of the collector, and heat absorbed by the heat transfer fluid. The results obtained show that the optical losses of the collectors of this type of plant represent one of the main causes of exergy losses. Additionally, it was possible to determine that for low-temperature applications, water allows the best exergetic use.
Prototype virtual assistant as a tool to support research activities at CORPOSUCRE
Authors: Pineda-Pertuz C M , Romero H J , Vergara J A , Morales A D , Sánchez A 
Published: July 2021

Abstract

Chatbots have become widely used tools in different fields of society, such as in industry, banking, health among other sectors. Their success is mainly that they can provide assistance to people quickly and in a timely manner no matter the time or place where the user is located. This project consisted of a virtual assistant (chatbot) based on artificial intelligence more specifically in the subfield of natural language processing (NLP). Basically what was intended with this prototype is to provide remote assistance to teachers and especially to students researchers of the Antonio José de Sucre Corporation answering their questions on research-related issues, particularly to support those who start in this field and wish to clarify some aspects related to the exercise of research within the institution. The system has been developed with open source tools in its latest versions, it is also modular in nature to facilitate its maintenance and easy integration with other programs, and in addition to being a web-oriented system can be deployed on a wide variety of devices which has greatly facilitated its validation.
A bibliometric analysis of the uses of the cocoa pod shell
Authors: Rincón-Quintero A D , Portillo-Valdés L A Del , Cárdenas-Arias C G , Tarazona-Romero B E , Rondón-Romero W L , Durán-Sarmiento M A 
Published: July 2021

Abstract
The research explores the use of cocoa pod shell (CPS) in rural areas and accessible to the cocoa farmer, applying VOSviewer software. The results show that the production of ethanol or biochar with CPS is not feasible, the first due to its low sugar content and the second, due to the requirement of processes with high temperatures for the extraction of different chemical compounds (i.e activated carbon). On the other hand, obtaining pellets represents a viable energy potential, since the calorific value is competitive with other biomass; Also, through anaerobic digestion under the ideal conditions, it can generate 55% in biogas of the solid matter used. Additionally, the ashes produced in direct combustion or pellets rep-resent an excellent catalyst, which can be used in transesterification, for the generation of biodiesel, used with other residual oils, giving a plus in the efficient use of resources.
Analysis of Envelopes Applied To Bioclimatic Architectures
Authors: Ascanio-Villabona J G , Sandoval-Rodriguez C L , Rincon-Quintero A D , Tarazona-Romero B E , Cárdenas-Arias C G , Quintero Ruiz A , Jaimes-Quintero K T 
Published: July 2021

Abstract
In the last decade, retrofitting strategies have been reviewed to improve energy efficiency and reduce the environmental impact of existing buildings [1]. A modernization strategy consists of an architectural design based on bioclimatic characteristics. The exploitation of climatic indicators and the use of passive strategies are among the central principles of this design approach [2]. The main objective of this study is to provide an extensive review of the different building envelopes with the adoption of high-performance materials or systems to improve human thermal comfort.
The effect of plug-in hybrid electric vehicle charging on fuel consumption and tail-pipe emissions
Authors: Mandev Ahmet , Plötz Patrick , Sprei Frances 
Published: July 2021

Abstract
Plug-in hybrid electric vehicles (PHEV) have an electric motor and an internal combustion engine and can reduce greenhouse gas emissions (GHG) from transport. However, their environmental benefit strongly depends on the charging behaviour. Several studies have analysed the GHG emissions from upstream electricity production, yet the impact of individual charging behaviour on PHEV tail-pipe carbon emissions has not been quantified from empirical data so far. Here, we use daily driving data from 7,491 Chevrolet Volt PHEV with a total 3.4 million driving days in the US and Canada to fill this gap. We quantify the effect of daily charging on the electric driving share and the individual fuel consumption. We find that even a minor deviation from charging every driving day significantly increases fuel consumption and thus tail-pipe emissions. Our results show that reducing charging from every day to 9 out of 10 days, increases fuel consumption on average by 1.85 ± 0.03 l/100 km or 42.7 ± 0.8 gCO2 km−1 tail-pipe emissions (± on standard error). Charging more than once per driving day has less impact in our sample, this must occur during at least 20% of driving days to have a noteworthy effect. Even then, a 10% increase in frequency only has moderate effect of decreasing fuel consumption on average by 0.08 ± 0.02 l/100 km or 1.86 ± 0.46 gCO2 km−1 tail-pipe emissions. Our results illustrate the importance of providing adequate charging infrastructure and incentives for PHEV users to charge their vehicles on a regular basis in order to ensure that their environmental impact is small as even long-range PHEVs can have a noteworthy share of conventional fuel use when not regularly charged.
Review of Spider Ecology During Carrion Decomposition, with a Field Study on Density and Taxa Richness in Pitfall Trap Captures of Geophilic Spiders (Aranea: Anyphaenidae, Corinnidae, Linyphiidae, Lycosidae, Salticidae)
Authors: De Jong Grant D , Meyer Florencia , Goddard Jerome 
Published: July 2021

AbstractDuring a recent pig carrion succession study in northwest Florida, United States, we noticed an abundance of spiders but found that literature on spider ecology at carrion is sparse and scattered. We compiled a literature review of 569 carrion succession studies, of which 37 studies specifically mentioned the presence of spiders, with less than a third providing species-level identifications and only half providing family-level identifications. Nineteen spider families have been reported at carrion in the literature. Spiders are recognized as generalist, opportunistic predators in carrion succession studies, but only 38% of the studies that mentioned spiders during carrion succession included any ecological information. Data on spiders in the present experiment were compared to background samples, finding that the difference in abundance was statistically significant for all spider species combined. Seven species of spiders from five families were identified from both background and carrion succession samples; statistical differences in abundance were found for three species: the linyphiid Florinda coccinea and the lycosids Tigrosa annexa and Pirata seminolus. The family Corinnidae is reported from carrion for the first time. This research reviews the existing literature on spider ecology during carrion succession, provides additional data on species identity and abundance, and demonstrates the potential significance of spiders in carrion ecology and forensic investigations.
Enhanced lateral flow testing strategies in care homes are associated with poor adherence and were insufficient to prevent COVID-19 outbreaks: results from a mixed methods implementation study
Authors: Tulloch John S P , Micocci Massimo , Buckle Peter , Lawrenson Karen , Kierkegaard Patrick , McLister Anna , Gordon Adam L , García-Fiñana Marta , Peddie Steve , Ashton Matthew , Buchan Iain , Parvulescu Paula 
Published: July 2021

Abstract

Introduction
Care homes have been severely affected by the SARS-CoV-2 pandemic. Rapid antigen testing could identify most SARS-CoV-2 infected staff and visitors before they enter homes. We explored implementation of staff and visitor testing protocols using lateral flow devices (LFDs).

Methods
An evaluation of a SARS-CoV-2 LFD-based testing protocol in 11 care homes in Liverpool, UK, including staff and visitor testing, plus a qualitative exploratory study in nine of these homes. The proportion of pilot homes with outbreaks, and outbreak size, were compared to non-pilot homes in Liverpool. Adherence to testing protocols was evaluated. Fifteen staff were interviewed, and transcript data were thematically coded using an iterative analysis to identify and categorize factors influencing testing implementation.

Results
In total, 1,638 LFD rapid tests were performed on 407 staff. Protocol adherence was poor with 8.6% of staff achieving &gt;75% protocol adherence, and 25.3% achieving $\ge$50%. Six care homes had outbreaks during the study. Compared to non-pilot care homes, there was no evidence of significant difference in the proportion of homes with outbreaks, or the size of outbreaks. Qualitative data showed difficulty implementing testing strategies due to excessive work burden. Factors influencing adherence related to test integration and procedural factors, socio-economic factors, cognitive overload and the emotional value of testing.

Conclusion
Implementation of staff and visitor care home LFD testing protocols was poorly adhered to and consequently did not reduce the number or scale of COVID-19 outbreaks. More focus is needed on the contextual and behavioural factors that influence protocol adherence.
Asymptotics of sample tail autocorrelations for tail-dependent time series: phase transition and visualization
Authors: Zhang Ting 
Published: July 2021

SummaryIn this article we develop an asymptotic theory for sample tail autocorrelations of time series data that can exhibit serial dependence in both tail and non-tail regions. Unlike with the traditional autocorrelation function, the study of tail autocorrelations requires a double asymptotic scheme to capture the tail phenomena, and our results do not impose any restrictions on the dependence structure in non-tail regions and allow processes that are not necessarily strongly mixing. The newly developed asymptotic theory reveals a previously undiscovered phase transition phenomenon, where the asymptotic behaviour of sample tail autocorrelations, including their convergence rate, can transition from one phase to another as the lag index moves past the point beyond which serial tail dependence vanishes. The phase transition discovery fills a gap in existing research on tail autocorrelations and can be used to construct the lines of significance, in analogy to the traditional autocorrelation plot, when visualizing sample tail autocorrelations to assess the existence of serial tail dependence or to identify the maximal lag of tail dependence.
Minimally invasive versus open pelvic exenterations for rectal cancer: a comparative analysis of perioperative and 3-year oncological outcomes
Authors: Kazi M , Kumar N A N , Rohila J , Sukumar V , Engineer R , Ankathi S , Desouza A , Saklani A 
Published: July 2021

Abstract

Background
This study compared the surgical and oncological outcomes of open and minimally invasive pelvic exenteration.

Methods
Patients who underwent pelvic exenterations for primary locally advanced rectal cancers with invasion of the urogenital organs (central and anterior disease) between August 2013 and September 2020 were reviewed retrospectively. Patients were categorized as undergoing open or minimally invasive surgery (MIS) and these groups were compared for perioperative outcomes and 3-year survival (overall, recurrence-free and local relapse-free survival). Multivariable Cox regression analysis was performed to assess the independent influence of approach of surgery and cancer features on recurrence-free survival (RFS).

Results
Of the 158 patients who underwent pelvic exenteration, 97 (61.4 per cent) had open exenterations and 61 (38.6 per cent) patients had an MIS resection (44 patients (72 per cent) using laparoscopy and 17 (28 per cent) using robotic surgery). There were 96 (60.8 per cent) total pelvic exenterations and 62 (39.2 per cent) posterior pelvic exenterations. MIS exenterations had significantly longer operative times (MIS versus open: 640 mins versus 450 mins; P &lt; 0.001) but reduced blood loss (MIS versus open: 900 ml versus 1600 ml; P &lt; 0.001) and abdominal wound infections (MIS versus open: 8.2 versus 17.5 per cent; P = 0.020) without a difference in hospital stay (MIS versus open: 11 versus 12 days; P = 0.620). R0 resection rates and involvement of circumferential resection margins were similar (MIS versus open: 88.5 versus 91.8 per cent, P = 0.490 and 13.1 versus 8.2 per cent, P = 0.342 respectively). At a median follow-up of 29 months, there were no differences in 3-year overall survival (MIS versus open: 79.4 versus 60.2 per cent; P = 0.251), RFS (MIS versus open: 51.9 versus 47.8 per cent; P = 0.922) or local relapse-free survival (MIS versus open: 89.7 versus 75.2 per cent; P = 0.491. On multivariable analysis, approach to surgery had no bearing on RFS, and only known distant metastasis, aggressive histology and inadequate response to neoadjuvant radiation (pathological tumour regression grade greater than 3) predicted worse RFS.

Conclusion
MIS exenterations documented longer procedures but resulted in less blood loss and fewer wound infections compared with open surgeries. In the setting of an experienced centre, the hospital stay, R0 resection rates and oncological outcomes at 3 years were similar to those of open exenterations.
Opening-Up Trajectories and Economic Recovery: Lessons after the First Wave of the COVID-19 Pandemic
Authors: Demirgüç-Kunt Asli , Lokshin Michael , Torre Iván 
Published: July 2021

Abstract
This article analyses the reopening process of countries in Europe and Central Asia after the first wave of the COVID-19 pandemic and provides evidence on the effects of different reopening trajectories and their timing and speed on economic recovery. The analysis indicates that countries that adopted a gradual, staged reopening experienced stronger economic recovery compared with the countries that rushed into lifting the restrictive measures before the pandemic was under control. Postponing lifting the restrictions until after the pandemic’s peak was reached has a positive impact on economic activity. Governance also matters: a higher level of trust in government is associated with increased economic activity among countries that carried out a gradual reopening process. There is also suggestive evidence that providing people objective data on the progress of the pandemic may speed up the recovery process. (JEL codes: D14, E21, and G51).