bluuebunny/crossref_metadata_2025 huggingface dataset:
The practical teaching of quantum mechanics
Authors: Chetty N.
Published: June 2020

The author teaches introductory quantum mechanics to third-year students at the University of Pretoria. Quantum mechanics is without a doubt one of the most challenging topics in the physics curriculum. It has been described as “All is waves, with nothing waving, over no distance at all! [1]” The mathematics of quantum mechanics is demanding, and the interpretation and conceptual understanding of the subject continue to occupy the minds of even some of our greatest thinkers today, more than a hundred years after its foundations were laid. Consequently, at the University of Pretoria, student performance has been notoriously low, students became discouraged, and absenteeism, plagiarism and copying plagued its delivery. The author intervened this year (2018) with a radically different approach to address these challenges. The outcomes have been significant, and the reviews (received from about 50% of the students) indicate that this new approach has worked beyond expectations. In this paper, the many different challenges faced and interventions made will be outlined.
Activities to enhance students’ understanding of acceleration: Part B
Authors: Molefe P , Khwanda M N
Published: June 2020

According to literature, the most important factor in education is to determine what students already know and to consider when teaching them. Unfortunately, there is a body of knowledge from physics education research revealing that we cannot simply build onto all existing knowledge that students have, because they contain misconceptions that differ from the accepted scientific understanding. As an example, students understand acceleration as an increase in the magnitude of speed or velocity. Based on that understanding, a brake pedal and a steering wheel of a motor car are not regarded as accelerators because they don’t increase the magnitude of speed. That is caused by the everyday usage of the term which differs with a scientific understanding. Other examples in mechanics where students have lack of understanding is their understanding of the concept of force. Literature revealed that students believe that a constant force causes an object to move with a constant speed, some force always acts in the direction of motion and that a larger mass falls faster towards the earth than a small mass. Some physics education researchers argue that productive elements in learners’ existing knowledge should be determined and used as bases for building scientific knowledge. Despite an earlier teaching of the concepts of motion in relation to acceleration from high school and in their first-year of physics at university, many of the students have difficulties in the problem solving required for the acceleration assessments. It is against this background that this paper presents and evaluates the impact of the activities that were designed to enhance students’ understanding of the concept of acceleration. The evaluation of the impact of intervention was done through Google forms. Preliminary analysis of the results reveals that if the vector nature of acceleration is emphasized, students would also value the importance of including the change in direction as the result of acceleration. The results implied that teaching mechanics should start with the impact of force in our everyday life since acceleration is the visible impact of force.
What is your favourite particle and why?
Authors: Wiener J , Woithe J
Published: June 2020

We have conducted a large-scale international study with high-school teachers (N=530) and high-school students (N=959) from all around the world to investigate and document what they consider as their favourite particles. We found five particles to be highly prominent in both groups, namely the Higgs boson, the neutrino, the electron, the photon and the gluon. Moreover, we did not find any significant differences with regard to the teachers’ and students’ nationality or gender. In this article, we present our findings in detail and give insight into the teachers’ and students’ justifications of why they chose a specific particle.
Practical preparation videos on a zero Rand budget
Authors: Fourie A , Lee E , van der Westhuizen I , Kroon R E
Published: June 2020

Due to limited equipment and laboratory space for practicals, students only have a relatively short time to complete their weekly practical. In this time they need to familiarise themselves with the apparatus that they are going to be using, carry out the experimental procedure, and obtain and interpret all the expected results. Their practical manual is comprehensive enough for them to prepare adequately for a practical session. But with the addition of a preparation video to supplement the practical guidebook, the hope was that students would arrive at a practical already familiar with the apparatus and with a clearer idea of what they are going to have to do. A video would also help cater for students with different types of learning methods, in line with universal design for learning. The project was undertaken to produce videos for half of our first semester second year practicals at The University of the Free State. No money was spent buying equipment or software, nor to pay professionals for their services. The assigned demonstrators for each practical were given the task to write the script for and present the video for their own practical. Evaluation of the effect of the videos were done by comparing the students’ experience and marks with two other groups. These are the practicals from the previous year, where all the practicals were presented in the same way, but none of them had introductory videos, and also to half of the current year’s practicals which did not have videos. The demonstrators also gave feedback on their experience, each of them were responsible for two practicals this year, one of them we made an introductory video for and the other we did not.
Game development for teaching physics
Authors: Kortemeyer G.
Published: June 2020

The paper describes two computer games which we developed to teach abstract physics concepts: A Slower Speed of Light, designed to teach Special Relativity, and Kirchhoff’s Revenge, designed to teach circuit laws. We report on experiences and research results using these games in physics lessons at college and high school level, user feedback, as well as information informally gathered from “Let’s Play” videos on YouTube. Finally, we describe plans for future developments.
Incorporating computational exercises into introductory physics courses
Authors: Kortemeyer G.
Published: June 2020

The paper describes the incorporation of computational exercises into introductory physics courses: mechanics, electricity and magnetism, and modern physics. While these courses traditionally emphasize symbolic and numerical calculations, as well as experimental methods, over the last decade, increasingly computational methods are incorporated into the curricula. The talk discusses opportunities for and examples of incorporating VPython projects, as well as logistics, learner collaboration, learning outcomes, and student feedback.
The “E3D+VET” Erasmus+ project: Interdisciplinary teaching and learning in VET centres through 3D printing
Authors: Pizzolato N , Limongelli M , Francesca A Di , Kirkar M , Koch V , Gomez Gomez V , Canavate Cruzado G , Fras M , Rein E , Perez Silva R
Published: June 2020

The “E3D+VET” (Erasmus+ for the immersion in 3D printing of VET centres) is an Erasmus+ KA2 project aimed at developing educational resources for the VET system, providing new competences to both teachers and students and serving as important means of innovation and acquisition of effective knowledge on interdisciplinary STEAM topics. The project started on October 2017 and it will last up to the end of March 2020. In this work, we present the main outcomes from the project activities carried out so far. In particular, after a description of the general objectives of the project, we introduce the methodology developed for making 3D-printing a valuable resource for supporting physics teaching in a highly motivating learning environment and three didactical exercises as examples of 3D-printing based tools that can support teachers in their physics class. As a part of the project plan, here we finally present the preliminary training program specifically designed for the teacher professional development about the knowledge of 3D-printing potential for an effective teaching of physics contents and, at the same time, for improving student transversal abilities.
A Bayesian Analysis for Circular Galaxies Using a Bose—Einstein Condensate as a Dark Matter Halo
Authors: Escamilla-Rivera C
Published: June 2020

In this paper we present an extension of a Bayesian study for a Bose–Einstein Condensate type halo surrounding a Schwarzschild–type black hole. The predictions obtained via the Thomas–Fermi approximation are tested using observations from SPARC galaxy rotation curves sampler with 10 circular galaxies and whose inclination (angle) is less that 80 deg. The statistical analysis is confronted with the Navarro–Frenk–White density profile model where we found that at the centre of galaxies is require a supermassive black hole with a constrain of log10
M/M
⊙ = 12.00 ± 0.73 to allow a BEC configuration at this stage. Also, we show that the proposed scenario can fit the galaxy rotation curves on average rate

χ

BEC

2

/

χ

NFW

2

=

1.49

.
A Practical Method for Solving the Inverse Quantum Scattering Problem on a Half Line
Authors: Karapetyants A N , Khmelnytskaya K V , Kravchenko V V
Published: June 2020

A method for solving inverse quantum scattering problems on a half line is proposed. It is based on the application of the transmutation operators and recent results on series expansion of the integral transmutation kernels. From the corresponding Gel’fand-Levitan equation a system of linear algebraic equations is derived for the coefficients of the Fourier-Legendre series expansion of the output (transmutation operator) kernel. It is shown that the knowledge of the very first coefficient is sufficient for recovering the potential and hence for solving the inverse problem. A numerical illustration is presented.
Properties of the Expansion of the Decaying Wave Solution in Terms of Resonant States
Authors: García-Calderón G
Published: June 2020

We consider the formulation of quantum decay in terms of resonant states and complex poles of the outgoing Green’s function of the problem to discuss some properties of the decaying wave solution that exhibit its non-Hermitian character and hence illustrate its departure from the standard formalism of quantum mechanics.
Structured Light by Rotating Au Nanoparticles in a Dynamic Distribution
Authors: Piña-Díaz A J , Martines-Arano H , Torres-Torres C
Published: June 2020

Herein is reported the potential impact of the optical Kerr effect exhibited by rotating plasmonic nanoparticles on the generation of structured light. The third-order nonlinear optical properties exhibited by a round continuously variable distribution of metal nanoparticles incorporated in a dielectric substrate were analysed. The nanosystems were studied by using the finite difference method and TiO2-supported Au nanoparticles explored by a vectorial two-wave mixing technique. Attractive applications for developing quantum functions assisted by mechano-optical effects can be considered.
Elementary SU(2) Operations to Manipulate the Entropy in Large 2-Level Quantum Systems
Authors: Delgado F
Published: June 2020

SU(2) operations are recurrently required in quantum information because of their simplicity. The SU(2) formalism states that quantum systems can be controlled easily, step by step, by means of such operations if convenient vector bases (normally composed by entangled states) are used as grammar. In this work, we explore the entanglement gained under such operations for the classes GHZ and W, as two well known representatives of maximal entangled states for larger systems.
Spectral Parameter Power Series Analysis of Supersymmetric Schrödinger Equations with Balanced Gain and Loss Potentials
Authors: Loredo-Ramírez S A C , Barrera-Figueroa V , Rabinovich V S
Published: June 2020

In this work the Zakharov-Shabat system is addressed to obtain a pair of supersymmetric Schrödinger equations. The scattering and resonance states of these equations are investigated. Explicit solutions for the equations are obtained in the form of power series of the spectral parameter. In the case of the scattering states, we obtain expressions for the transmission and reflection coefficients. In the case of the resonance states we obtain the characteristic equation that defines their complex energies. We show that finding approximate complex energies of the resonance states reduces to calculating polynomial roots from certain characteristic polynomial. Some cases of interest are numerically implemented.
Analysis of Singularities and Internal Dynamics of Electron Beams
Authors: Jimenez-Trejo G , Kunold A
Published: June 2020

In this work we present an analysis of phase singularities in Laguerre-Gaussian beams. The cases to be analyzed are static and dynamic singularities. We consider the composition of canonical and kinetic currents around the singularities and velocities on each momentum state. We compare the behavior of time-dependent and stationary systems. We obtain the topological charge numbers that characterize the rotation of currents around the singularities. Finally, we present some analytical and numerical results to illustrate our model.
Low-loss and flat dispersion umbrella-shaped and porous-core photonic crystal fiber for terahertz applications
Authors: Gomez-Cardona N , Espinal Zapata S , Montoya-Cardona J , Reyes-Vera E
Published: June 2020

A novel design of a single-mode photonic crystal fiber for applications in the terahertz region is proposed and numerically analyzed. The geometrical and optical parameters of the structure are estimated by using algebraic expressions while the guidance properties are calculated by using the full-vector finite element method. The porous-core of the fiber is suspended by eight equally spaced bridges connected to an outer cladding. The obtained results show that by adjusting the structural parameters appropriately, low-loss and flat dispersion properties could be easily achieved. The numerical results show that our best configuration, with a 60% filling fraction, exhibits a low effective material loss, below 0.2 dB/cm, and a flattened dispersion behavior in the frequency range from 0.79 THz to 1.5 THz.
Spherical representation of light detection and ranging data for three-dimensional object detection
Authors: Pamplona J , Herrera-Ramirez J , Madrigal C
Published: June 2020

Autonomous vehicles are one of the most attractive applications for light detection and ranging sensors, where they help with scene understanding. For this understanding, object detection is crucial, and it must be done in a frame by frame basis. This detection on a single frame is a challenging task due to the sparse and disordered nature of the information. This paper presents an alternative spherical representation for this data aiming to improve object detection. This proposal registers the light detection and ranging data in a 2-dimensions angle map using most of the 3-dimensions points in three layers, adding reflectivity information, and a logarithmic representation of distance. For evaluating this representation, we employed an object detector based on the algorithm: you only look once version 3, and we used a public reference dataset of 3-dimensional objects for training. This framework yielded a classification accuracy of 85.9% and 74.5% of intersection over union factor when estimating seven classes simultaneously. This approach presents an alternative for processing this data that helps to benefit the most from the light detection and ranging information with high accuracy, helping in the reduction of the associated risks of autonomous vehicles.
Bone segmentation in computed tomography images using a Hermite-based approach
Authors: Vargas-Quintero L , Barba-J L , Calderon J A , Torres-Moreno C
Published: June 2020

Computed tomography images of the human bone system are essential for evaluation of abnormalities and disease detection. Structural and anatomical information can be assessed with computer tomography with the aim of performing diagnosis, planning and treatment evolution. Automatic segmentation can provide a fast, objective evaluation and quantification of the bone conditions. In this work, we propose a segmentation technique consisting of a region growing method implemented in the Hermite transform domain. The Hermite transform provides a powerful mathematical tool which is useful for extraction of the image features. These are obtained through a set of Hermite coefficients. A seed or a pre-segmentation is used to initialize the region growing approach and coefficients of the Hermite transform are posteriorly employed to grow the initial shape. We have used Hermite coefficients up to second order. Edge, gray level and zero crossing information obtained with the Hermite transform are configured for the growing criterion. Several computer tomography images were used for evaluation. Different metrics were employed for performance assessment and we have compared results of the proposed method against the manual segmentation. The obtained results demonstrate that the HT substantially improves the texture classification which is directly reflected into a better segmentation of the bone tissues. The region growing algorithm presents a better performance if it is applied to Hermite coefficients compared to the original method which is performed on the original image space.
Classification of hyperspectral images of the interior of fruits and vegetables using a 2D convolutional neuronal network
Authors: Barrera J S , Echavarría A , Madrigal C , Herrera-Ramirez J
Published: June 2020

This work evaluates the performance of a Deep Learning technique for classification of challenging hyperspectral images of the interior of fruits and vegetables when they are combined. Some of these samples have low contrast, similar colour features, and their skins or characteristic shapes are lost when cut to expose their interiors. We implemented a two-dimensional convolutional neural network for this classification task and compared their results against the technique of support vector machines. We randomly selected a group of 13 hyperspectral images from a public database containing information of the interior of 42 fruits and vegetables. Using parts of these 13 selected images, we constructed three artificial hyperspectral images merging these parts differently. We applied the two proposed techniques over the three of them. The comparison of the classification results shows that the two-dimensional convolutional neural network over-performs the support vector machine in all three composite images. The two-dimensional convolutional neural network exceeded 98% classification accuracy in all of them. These results show that the two-dimensional convolutional network benefits from the spatial and spectral data in the images obtaining proper levels of classification even in samples mixed in complex contexts, as it can occur in the food or pharmaceutical industries.
A reconfigurable scintillator-based small array facility for cosmic ray studies
Authors: Riggi F , La Rocca P , Nicotra D , Parasole O , Pinto C
Published: June 2020

The first operational tests of a low-cost, reconfigurable mini-array for cosmic rays are here reported. Such facility is intended mainly as an educational tool for master and PhD students, to carry out quantitative investigations in cosmic ray physics. Each detection module is based on a small scintillator tile, optically coupled to a Wavelength Shifter (WLS) bar and a Silicon photomultiplier for light collection and readout. An Arduino MEGA board is used for trigger, data acquisition and storage. GPS time stamping of the events is also provided. The tests carried out with a set of 30 detection modules, spread over an area of about 50 m2, are here reported. About 300k shower events were collected during a period of 13 days, with a trigger involving at least a three-fold coincidence between the modules. Individual rates of the modules, together with environmental data (pressure and temperature) were also measured along the acquisition period. Multiplicity distributions in stand-alone mode and in coincidence with an additional detector located some distance apart were extracted from the data. The dependence of the shower rate on the atmospheric pressure was also investigated.
Machine learning-based integration of large-scale climate drivers can improve the forecast of seasonal rainfall probability in Australia
Authors: Feng Puyu , Wang Bin , Liu De Li , Ji Fei , Niu Xiaoli , Ruan Hongyan , Shi Lijie , Yu Qiang
Published: June 2020

Probabilistic seasonal rainfall forecasting is of great importance for stakeholders such as farmers and policymakers to assist in developing risk management strategies and to inform decisions. In practice, there are two kinds of commonly used tools, dynamical models and statistical models, to provide probabilistic seasonal rainfall forecasts. Dynamical models are based on physical processes but are usually expensive to operate and implement, and rely overly on initial conditions. Statistical models are easy to implement but are usually based on simple or linear relationships between observed variables. Recently, machine learning techniques have been widely used in climate projection and perform well in reproducing historical climate. For these reasons, we conducted a case study in Australia by developing a machine learning-based probabilistic seasonal rainfall forecasting model using multiple large-scale climate indices from the Pacific, Indian and Southern Oceans. Rainfall probabilities of exceeding the climatological median for upcoming seasons from 2011 to 2018 were successively forecasted using multiple climate indices of precedent six months. The performance of the model was evaluated by comparing it with an officially used forecasting model, the SOI (Southern Oscillation Index) phase model (SP) operated by Queensland government in Australia. Results indicated that the random forest (RF) model outperformed the SP model in terms of both distinct forecasts and forecasting accuracy. The RF model increased the percentages of distinct forecasts to 64.9% for spring, to 71.5% for summer, to 65.8% for autumn, and to 63.9% for winter, 1.4 ∼ 3.2 times of the values from the SP model. Forecasting accuracy was also greatly increased by 28%, 167%, 219%, and 76% for four seasons respectively, compared to the SP model. The proposed rainfall forecasting model is based on readily available data, and we believe it can be easily extended to other regions to provide seasonal rainfall outlooks.
Study on the addition of Caulerpa lentillifera on growth and survival rate of saline tilapia Oreochromis niloticus, L
Authors: Arisa I I , Zulfikar Z , Muhammadar M , Nurfadillah N , Mellisa S
Published: June 2020

Saline tilapia (Oreochromis niloticus, L) is potential to be cultured due to its high content of nutrition. This study aims to determine the optimal dosage of Caulerpa lentillifera meal in feed for growth and survival rate of saline tilapia. This research was conducted on August to September, 2018 at Brackish Water Aquaculture Development Center, Aceh, Indonesia. The study used an experimental method with a completely randomized design (CRD) with 5 treatments of meal dosage and 4 replications, namely; A = 0 g, B = 10 g, C = 20 g, D = 30 g, and E = 40 g Caulerpa lentillifera meal Kg−1 feed. The observed parameters included absolute weight gain, absolute length growth, daily growth rate, feed effeciency and survival rate. The results showed that the addition of Caulerpa lentillifera meal in feed significantly (p <0.05)affected the growth and survival rate of saline tilapia. The optimal dosage of meal was 20 g Caulerpa lentillifera meal Kg−1 feed a(treatment C).
Profile of organic material source and environmental condition in the sediment of Badek and Mewek River, Malang, Indonesia
Authors: Ulinuha D , Andayani S , Hertika A M , Kilawati Y
Published: June 2020

The sediment characterizations and water quality in the Badek and Mewek River are observed to know the origin of organic materials and environmental conditions in those rivers. The total carbon of the sediment was analyzed using a total carbon analyzer, while total nitrogen was measured by using the indophenol blue method. Total bacterial number in the sediment was estimated using the slow stirring method. Dissolved oxygen (DO) of water was analyzed using Winkler Method, chemical oxygen demand (COD) was analyzed using a dichromate-titrimetric method, and the pH of the water was measured using pH meter. The result showed a C/N ratio of around 20, indicating that organic materials in the Badek and Mewek River might be coming from the mixing of aquatic origin and terrestrial sources. Badek River showed a higher C/N ratio indicating a more substantial influence of terrestrial organic material compared to Mewek River. The total bacterial number in the sediment of Badek River might be related to the low water quality in that river.
Effect of ethanol immersion time on parthenogenesis
Authors: Faqih A R , Soeprijanto A , Anitasari S
Published: June 2020

The purpose of this research was to investigate the probability of common carp (Cyprinus carpía L.) egg parthenogenesis activated by ethanol. The method used was experimental design, with 7 treatments and 3 replications. The treatment includes positive control (using sperm) and negative control (without sperm). The immersion times in 7% ethanol were 2; 2.5; 3; 3.5 and 4 minutes. The main parameter was percentage of activated and development egg. The support parameters were temperature, DO, and pH values. The results showed that sperm submerged in ethanol 7% for 2 minutes displayed very significant influence (P<0.05) for activation and development egg with maximum embryo development reached was bastula phase. Water quality data showed that the temperature ranged from 20.1-22.7°C, DO 6.72-6.84, and pH in the range of 7.19-7.55.
Impact of anthropogenic activity and lusi-mud volcano on fish biodiversity at the Brantas Delta, Indonesia
Authors: Risjani Y , Santoso D R , Couteau J , Hermawati A , Widowati I , Minier C
Published: June 2020

Investigation to examine the impact of anthropogenic activity and unstoppable hot mudflow by the “LUSI” mud on the environment and fish biodiversity has been carried out. Water quality analyses including heavy metal and phenol concentration from the site were determined using AAS and spectrophotometer. Physico-chemical analyses at the location showed high levels of pollutants: including a high level of phenol and heavy metal such as lead, cadmium and mercury. The discharge of these pollutants into the river body, estuaries and coastal environment influenced fish biodiversity. Data on fish diversity taken by comparing fish data from reports after the eruption in 2006 with the data before the eruption from the previous study shows a decrease of diversity. Seven years after the eruption, there were nine important economic species consumed by local people of the deltas need to be taken seriously.
Stress response of Asian redtail catfish (Hemibagrus nemurus) fingerlings subjected to various pH exposure
Authors: Prakoso V A , Sinansari S , Priadi B , Sundari S , Kristanto A H
Published: June 2020

Asian redtail catfish (Hemibagrus nemurus) is one of the economic freshwater fish species in Indonesia. There is still a lack of information regarding water quality tolerance of Asian redtail catfish. Therefore, this study was conducted to obtain information on the stress response of Asian redtail catfish under various pH exposures. The experimental fish was the second generation of domesticated Asian redtail catfish from the Cirata population (Length: 11.7 ± 0.6 cm; Weight: 13.2 ± 1.6 g). The pH treatment in this experiment was low pH (4-5), optimal pH (6-9), and high pH (10-11) with three replicates in each treatment. Stress response was observed by measuring blood glucose and plasma cortisol. Moreover, fish behavior and survival were also observed. Results showed that glucose level of Asian redtail catfish fingerlings was higher at low pH treatment (258.8 ± 75.1 mg/dL) than optimal (58.7 ± 7.5 mg/dL) and high pH treatment (151.0 ± 21.5 mg/dL) (P<0.05). Cortisol level at low (34.02 ± 3.16 IU) and high pH (32.88 ± 13.85 IU) was significantly higher than optimal pH treatment (12.56 ± 5.18 IU) (P<0.05). Low and high pH exposure to Asian redtail catfish increased their cortisol and glucose levels, which will lead them to mortality.
Species composition of puerulus spiny lobsters from the South Sea of Pacitan of East Java, Indonesia
Authors: Setyanto A , Saputra W A , Soemarno  , Wiadnya DGR , Prayogo C
Published: June 2020

There are about six species of tropical spiny lobsters within a group of Panulirus inhabit Indonesia archipelagic waters. A lobster fishery is among relevant national fisheries products. Their social, economic, and ecological contributions to the country are significant. Hence, the lobster’s resource sustainable use always becomes a challenge for the management authority. Life phase distribution of marine organisms in space and time is critical information for management. The equivalent study can be phrased for the lobster population in the South Sea of Java Island of Eastern Indian Ocean. The purpose of this study was to develop formulations to protect ecosystems and conserve lobster resources. Distribution of pueruli larvae of spiny lobster of Panulirus species was surveyed in the South Sea of Pacitan, East Java from January to February 2019. The number of pueruli larvae caught were counted and compared among the species. An ANOVA test was performed for data analysis. There were four species of lobster found. The dominant species wasPanulirus homarus(Scalloped spiny lobster). It was followed byP. versicolor(Painted spiny lobster), andP. ornatus(Ornate spiny lobster). The least dominant wasP. pennicillatus(Pronghorn spiny lobster). Comparative study on life stage distribution concerning to larval dispersal may support the connectivity hypotheses of the lobster population in the region.
The effect of phlorotannin Sargassum sp. extract on colon profile of diabetic rats
Authors: Faricha F , Firdaus M
Published: June 2020

Diabetes mellitus is a metabolic disorder marked by hyperglycemia. Polyphenol is capable of being scavenger of free radicals by transferring its hydroxyl atom. Polyphenol, which contained in brown algae, is phlorotannin. This study aimed to investigate the effects of phlorotannin from Sargassum sp. on blood glucose and histopathology of the colon of diabetic rats. Research steps were extraction of a phlorotannin, the establishment of the diabetic model, general histological staining, histopathology analysis, and determination of phlorotannin contain. This research was comprised of seven groups and five replications of treatment. Diabetic rats were prepared by injection of 40 mg/kg BW streptozotocin in intraperitoneal. The results showed that Sargassum sp. extracts were capable of diminishing blood glucose level, likewise repairing the histopathology of the colon. A dose of 600 mg/kg BW is the best dose of extract Sargassum sp. on improving the colon profile of diabetic rats.
Economic and Technical Analysis of Universal Accessibility in Social and Private Housing in Chile
Authors: Ferrada X , Valderrama C , Fuentes-Contreras C
Published: June 2020

According to studies of accessibility in Chile show that the country is aging, by 2050 the population of the third age will increase to more than double where, in addition, the third of that group will develop some type of disability, with the physical type prevailing.

Under this problem, Chile has modified his regulatory building body (OGUC) in 2016 establishing new design standards in order to have homes with basic characteristics of accessibility universal. But these modifications are not retroactive in housing policy.

Because of this, the present study analyzes the incorporation of accessibility standards into social and private housing that are already built. Technically, it discusses basic solutions to comply with the regulatory approaches and then analyze the economic impact of the solutions, along with the modifications of non-structural elements for regulatory compliance without changing the useful surface of the housing. Showing to achieve accessibility in an existing private home the cost can increase by 0.08 UF/m2 and for social housing by 0.05 UF/m2.

The study shows that with a good projection of the evolution of the people who will inhabit the houses, in conjunction with decisions from the design stage, they can have affordable housing at a low cost preventing the owner have to make large investments for adapt his house to any situation of disability that may be present throughout life.
BIM for Sustainable Management in Existing Hospitals
Authors: da Casa F , García R , Echeverría E , Celis D’Amico F , Nope A , Domínguez P , Chías P
Published: June 2020

The main objective of this communication is to determine the characteristics and requirements of the BIM model, in particular in relation to the BPS energy analysis, to be used as a project tool that supports sustainable management in existing hospital establishments. With this objective, BIM architectural models and environmental simulations of representative buildings in Chile and Spain were carried out to review and propose attributes of sustainable models that allow a better adaptation to growth and flexibility from the early stages of design and restructuring. This study associates low energy consumption strategies for hospital establishments. The study is aimed at the integral management of both the operation of the building and all the services involved in its use and exploitation. This will allow to discuss the paradigm changes regarding the training of the architect and the specialists involved in the design, construction and operation of more sustainable projects.

A post-publication change was made to this article on 3 Jul 2020 to correct an author affiliation.
Thermal Sensation Assessment at Different Types of Covered Outdoor Spaces in Barranquilla - Colombia
Authors: Rodriguez-Potes L , Villadiego K
Published: June 2020

The notion of comfort applies to productivity, hygiene and air treatment and to the dimensions of sustainability and energy saving. This research analyzes thermal sensation and microclimatic conditions at several outdoor spaces with different combinations of parameters: artificial cover, vegetation cover and without cover. The evaluation scale used in this study is the seven-point ASHRAE scale, which is used to determine people’s psychological reactions to these spaces. The results show that the cover material affects the air temperature and thermal conditions of the spaces. The best thermal comfort conditions were found under trees and a tensioned membrane structure. These cover materials act by blocking radiation and projecting shade on pedestrians, the floor and the walls, which influences the thermal sensation. The results of this research are intended to contribute knowledge for the development of urban design guidelines that take into consideration the microclimatic conditions of tropical cities.
Critical Mapping of Indicators for Smart Cities Evaluation
Authors: Massara B , Santo K
Published: June 2020

Sustainable urban development is extremely important, if not imperative, for city managers and policy makers. Nowadays, the use of Information and Communication Technologies announces assertive, sensitive and economic solutions. This research aims to introduce smart city indicators based on critical and updated diagrammatic digital analysis regarding issues such as mobility, transportation, environment, housing, governance and security faced with concepts as innovation, sustainability and others. In order to achieve this goal, it is offered an original and relational mapping of indicators created from information collected in different sources such as texts by well-known authors such as Guimarães [1], Greenfield [2], Weiss [3] institutional websites such as Brazilian Smart Cities Network [4], Urban Systems [5] publications and legal regulations such as NBR ISO 37122 [6]. Thus, this relational mapping will highlight graphically and visually the relations between the types of technologies available and how they have been used and applied. In a nutshell, we offer a diagrammatic approach oriented to create a useful indicator analysis guide based on available technologies, populations’ needs and, more importantly, hope to provide better understanding about smart cities rankings and indicator regarding the well-being of people interacting with urban infrastructure, in special with mobility and urban devices.
Impact of Geographic Location on Energy and Fossil Fuel Demand as well as Climate Change in the Life Cycle of Tourist Accommodation Establishments in Chile
Authors: Ovalle X , Muñoz E
Published: June 2020

Tourism is a rapid-growth industry on a global scale that includes transportation, excursions and tourist accommodation establishments. In turn, these activities have an impact on energy demand, to achieve thermal comfort, in addition to environmental impacts such as climate change and fossil fuel demand. These impacts vary depending on energy sources, water and solid waste treatment, and availability of resources, among other factors. The objective of this study was to evaluate the influence of geographic location on energy demand to attain thermal comfort and to assess the environmental impacts of tourist accommodation establishments in Chile. DesignBuilder software was used to evaluate energy demand for thermal comfort in the establishments, by measuring thermal transmittance through roofing, walls, flooring, doors and windows of the establishments, following the MINVU (NTM 11) technical standard. Moreover, different building materials were modelled for each establishment, depending on their geographic location. Climate change and fossil fuel demand were analyse using a life cycle assessment in accordance with ISO 14044, using a functional unit of 1 guest night. Inventory and impact assessment data were modelled using SimaPro software, thereby obtaining different energy demands based on the establishment’s geographic location. Northern establishments were shown to have greater impact on climate change and fossil fuel demand with coal being most relied upon in this respect and CO2 the substance chiefly emitted in environmental impact on climate change (a carbon footprint of 15.68 kg CO2 equals one guest night). This study determines that geographic location impacts energy demand, climate change and fossil fuel demand.
Diagnosis of the Generation of Solid Waste in the Construction of a Building Under the Approach of Industrial Ecology
Authors: Bracho L , Martinez P
Published: June 2020

The construction industry generates 30% of the total solid waste in Chile, causing a high impact on the environment, due to the multiple inefficiencies generated in different stages of the development cycle of the projects, involving design, quality and characteristics of the materials in the construction of the referred project. The study covers only solid waste generated in the construction of high buildings, focusing on the area known as Industrial Ecology (IE). The IE aims to achieve that industrial systems have a behavior similar to that of natural ecosystems, allowing the linear model of production systems to become a cyclical model, promoting the interactions between economy, environment and society, developing the efficiency of industrial processes. The two main tools of IE were used: The Material Flow Analysis (MFA) and the Life Cycle Analysis (LCA). MFA was used to obtained indicators from the main products or raw materials that are used and that are transformed into a waste in high buildings construction processes, such as: concrete, wood, iron, sheetrock, tiles and ceramics. The LCA served to identify, quantify and characterize the different potential environmental impacts in the area, such as: climate change, depletion of natural resources and occupation of soils, associated with each of the stages of existence of a product. After these two analyses, it was possible to identify the stage of the process in which the main losses of materials occur in the construction of a high building. In addition, it was possible to identify alternative scenarios of solid waste management among different companies that want to transform this waste into raw materials or by-products, saving production costs, reducing environmental impact and creating different types of industrial symbiosis.
Albedo Quantification Using Remote Sensing Techniques. Cool Roof in the Metropolitan Area of Mendoza-Argentina
Authors: Alchapar N L , Colli M F , Correa E N
Published: June 2020

The presence of cities raises air temperature. The growth of sealed urban surfaces and anthropogenic heat modifies the natural energy balance increasing the CO2 emissions of a city. A strategy to reduce urban temperatures and energy consumption is the widespread application of cool materials -with high albedo and high emissivity- in the urban envelope. Roofs are the horizontal opaque surfaces most exposed to solar radiation and are therefore the ones that absorb the highest thermal load of a building. The objective of this research is to design a procedure that allows the discrimination the different roofing materials within the Metropolitan Area of Mendoza, Argentina, to determine the possible energy savings and improvements in urban microclimatic conditions associated with the increase of albedo in the roofs of the city. The methodology is based on a supervised classification of roof materials using spectral signatures with QGIS 3.2 ‘Bonn’ software. For this purpose, images from the Sentinel 2a platform were used and 3 series of spectral signatures were obtained from built urban areas. The results show that the materials mainly used in the roofs of the city of Mendoza are membranes (74%), zinc sheet (14%) and traditional tiles (13%). These findings represent an efficient tool to quantify the energy and environmental effects of regulating albedo values in urban roof.
Microclimatic Strategies for “Vila Residencial da UFRJ”: Mitigating the Effects of High Temperatures
Authors: Rocha E , Paiva A L , Drach P R C , Barbosa G S
Published: June 2020

The urban morphology and both pavement and edifications materiality influence directly on the microclimate. Thus, urban form and microclimatic researches cooperate with the understanding of this interaction, besides they may evidence solutions to attenuate these negative effects in weather, such as the heat-island effect, which makes the environment comfort worse in cities of the tropical countries. In previous studies, a diagnostic of “Vila Residencial da UFRJ”, situated on Rio de Janeiro, Brazil, has been done considering the variation of intra-urban temperature. The air temperature values have been measured and simulated in the interior of the Village as well as in its surroundings, in other to find the most intense heat areas. From the diagnostic about the region (urban morphology forwarding; climate variables and socioeconomic information), analysis and proposals of intervention strategies have been developed, tested with a broader series of computational simulations. Following the study, this article presents the developing process of an illustrated guide, in clear and accessible language, for the local people and leadership, exposing the relation between the factors that can increase temperature and the indicated means of mitigating them. The strategies were thought for the broader scenario of the Residential Village, fulfilling the needs of environmental comfort and the possibility of implementation according to local peculiarities, such as: the lack of space in some sidewalks and streets, making impracticable the planting of tree species; the need to work with low-cost materials and local labor, very often few specialized ones; absence of space between the buildings, among others.
Evaluation of Industrial Ashes in Cement Replacement in Mortars
Authors: Rivas J , Letelier V , Parodi C , Manosalva M
Published: June 2020

It is well known that cement production has a high negative impact on the environment. This fact, in conjunction with the high demand for this product worldwide, has created concern over how to reduce its use. Various materials have been tested as partial or total replacements for cement, one of which is biomass ash. In this article we report the preparation of test samples of mortar using two types of biomass ash, the first of forest origin and the second agricultural; both were used to replace cement in proportions of 10%, 20% and 30%. The test samples were assayed for compression and flexion after 7, 14, 28 and 90 days. After 28 days the apparent density, open porosity, absorption, capillarity and ultrasound velocity were measured. All the results of the series were compared with a control mortar. In the compression and flexion assay, a higher resistance than the control mortar was obtained with 10% replacement of both types of ash after 90 days, however with 20% and 30% ash the results were inferior to traditional mortar. There was an increase in the absorption percentage and porosity as the percentage of cement replacement increased; this increase was smaller for ash from agricultural biomass than ash from forest biomass. The density diminished as the percentage of replacement material increased, but the change was smaller with ash from agricultural biomass; this may be attributed to a filler effect produced by its granulometric distribution.
Thermal and Mechanical Analysis of Plywood Boards Thermally Enhanced with Phase Change Materials
Authors: Fernández V , Valderrama-Ulloa C , Rouault F , Schmitt C , del Río R , Vasco D
Published: June 2020

Adding Phase Change Materials (PCM) in construction elements and materials increase their thermal mass, which may reduce temperature variation of indoor environment and improve thermal comfort of occupants. The present paper aims to study the thermal and mechanical impacts of embedding microencapsulated PCM in the adhesive of plywood boards. Mechanical properties of samples are measured using a standardized bending test; thermal mass is estimated with a homemade experimental setup based on a heated bed and two thermocouples. Tests were carried out on three different samples: a reference sample without PCM, a second sample with adhesive containing 25% of PCM, and a third sample with 30% of PCM. The most relevant results from the study showed that the mechanical properties of plywood boards were not significantly affected by the PCM, and the thermal mass was improved up to 19% on a variation of 30°C.
Assembly of Stay-In-Place Concrete Blocks Using a Robot
Authors: García R , Perez A , Pulido J A , Ulloa P , Forcael E
Published: June 2020

This work presents an experiment where a constructive system with hollow blocks is assembled using a robot. These blocks form a stay-in-place support to receive a mixture onsite, generating a monolithic concrete wall with vertical steel reinforcements, as well as providing thermal and acoustic insulation capabilities. The assembly system is tested with an industrial robotic arm, programmed to assemble the blocks following the layout of a building. The tests demonstrate the technical feasibility for execution onsite, with productivity advantages and suitable finishes. Thermal and acoustic performance tests have also been carried out to determine the fillings and structural studies for the complete building layout, along with digital modelling of the design and construction management. The assembly tests have shown the speed and versatility of the robotic system, although the planning and installation of the equipment considering the building as a whole must be developed further.