Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.58658
Superna Kumari, Z. Memon
Before product development, Requirement Engineering (RE) is the fundamental need to know customer preferences for any product. Traditionally, RE is carried out in several ways, particularly by conducting interviews, questionnaires, surveys etc. but these methods provide limited amount of data. As user’s preferences vary from country to country for any type of application, it is very hectic and time consuming to collect user requirements from different countries manually. As the internet is widely used now a days, a large number of customer’s reviews are available online that can be used to obtain the requirements for any product without manual work. Online customer reviews can be divided into three types: user experience, bugs and feature requests. Among these 3 categories, feature requests can be very useful for stakeholders (analysts/ requirements engineers) to acquire the requirements of each application. So, the approach is proposed for feature requests extraction from mobile application reviews of travel industry. In this paper, 4 categories of mobile apps of travel industry belonging to 5 countries have been extracted from Google Play Store and Apple Store. For each category, data from 5 different mobile applications have been considered. Since, the review of users from different countries is in their respective language, those reviews are translated into a standard language i.e. English, and then feature requests from these reviews have been extracted. After that, features are retrieved from user reviews and topic modeling is performed on extracted features since one or more features can be modelled under one topic. To know the opinions of users for any feature request, sentiment analysis is also performed on feature request sentences. These feature requests are also classified as Functional and Non-functional Requirements since it is very useful for application developers to improve or maintain the product to better facilitate the application users
在产品开发之前，需求工程(RE)是了解客户对任何产品偏好的基本需求。传统上，可再生能源是通过几种方式进行的，特别是通过进行访谈，问卷调查，调查等，但这些方法提供的数据量有限。由于用户对任何类型的应用程序的偏好因国家而异，因此手动收集来自不同国家的用户需求是非常忙碌和耗时的。随着互联网的广泛使用，大量的客户评论可以在网上获得，无需人工操作即可获得对任何产品的需求。在线用户评论可以分为三种类型:用户体验、bug和功能请求。在这三种类型中，功能请求对于涉众(分析师/需求工程师)获取每个应用程序的需求非常有用。为此，提出了一种从旅游行业移动应用评论中提取特征请求的方法。本文从Google Play Store和Apple Store中提取了5个国家的4类旅游行业移动应用。对于每个类别，我们都考虑了来自5个不同移动应用程序的数据。由于来自不同国家的用户的评论是用他们各自的语言，这些评论被翻译成一种标准语言，即英语，然后从这些评论中提取功能请求。之后，从用户评论中检索特征，并对提取的特征执行主题建模，因为一个或多个特征可以在一个主题下建模。为了了解用户对任何特征请求的意见，还对特征请求句子进行了情感分析。这些特性请求也被分为功能性需求和非功能性需求，因为它对应用程序开发人员改进或维护产品以更好地为应用程序用户提供便利非常有用
{"title":"Extracting feature requests from online reviews of travel industry","authors":"Superna Kumari, Z. Memon","doi":"10.4025/actascitechnol.v44i1.58658","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.58658","url":null,"abstract":"Before product development, Requirement Engineering (RE) is the fundamental need to know customer preferences for any product. Traditionally, RE is carried out in several ways, particularly by conducting interviews, questionnaires, surveys etc. but these methods provide limited amount of data. As user’s preferences vary from country to country for any type of application, it is very hectic and time consuming to collect user requirements from different countries manually. As the internet is widely used now a days, a large number of customer’s reviews are available online that can be used to obtain the requirements for any product without manual work. Online customer reviews can be divided into three types: user experience, bugs and feature requests. Among these 3 categories, feature requests can be very useful for stakeholders (analysts/ requirements engineers) to acquire the requirements of each application. So, the approach is proposed for feature requests extraction from mobile application reviews of travel industry. In this paper, 4 categories of mobile apps of travel industry belonging to 5 countries have been extracted from Google Play Store and Apple Store. For each category, data from 5 different mobile applications have been considered. Since, the review of users from different countries is in their respective language, those reviews are translated into a standard language i.e. English, and then feature requests from these reviews have been extracted. After that, features are retrieved from user reviews and topic modeling is performed on extracted features since one or more features can be modelled under one topic. To know the opinions of users for any feature request, sentiment analysis is also performed on feature request sentences. These feature requests are also classified as Functional and Non-functional Requirements since it is very useful for application developers to improve or maintain the product to better facilitate the application users","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"11 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84178889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.58653
Dr. Shini Renjith, A. Sreekumar, M. Jathavedan
Social media has significantly influenced modern lifestyle and the way in which most of the industries operate their business. Social media data refers to the contents created by users during their social interactions in the form of text, sound, visuals, etc. It has now evolved as the major source of information for different industry verticals like retail, marketing, advertising, tourism, hospitality, education, etc. The huge volume of data resulted in the necessity for better and efficient procedures for personalized information retrieval. Traditional data mining and information retrieval techniques based on content-based and/or collaborative filtering proved computationally costly and less scalable against the volume it must deal with. Adoption of clustering techniques is a potential solution for this problem as it can minimize the amount of data required to be managed in industrial applications like recommender systems. This empirical research focuses on evaluating multiple clustering algorithms with the goal of finding an ideal solution for clustering numerical data extracted from social media sources. Three different publicly available datasets with varying number of attributes and records from tourism domain are used for the experiments conducted as part of this work
{"title":"An empirical research and comparative analysis of clustering performance for processing categorical and numerical data extracts from social media","authors":"Dr. Shini Renjith, A. Sreekumar, M. Jathavedan","doi":"10.4025/actascitechnol.v44i1.58653","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.58653","url":null,"abstract":"Social media has significantly influenced modern lifestyle and the way in which most of the industries operate their business. Social media data refers to the contents created by users during their social interactions in the form of text, sound, visuals, etc. It has now evolved as the major source of information for different industry verticals like retail, marketing, advertising, tourism, hospitality, education, etc. The huge volume of data resulted in the necessity for better and efficient procedures for personalized information retrieval. Traditional data mining and information retrieval techniques based on content-based and/or collaborative filtering proved computationally costly and less scalable against the volume it must deal with. Adoption of clustering techniques is a potential solution for this problem as it can minimize the amount of data required to be managed in industrial applications like recommender systems. This empirical research focuses on evaluating multiple clustering algorithms with the goal of finding an ideal solution for clustering numerical data extracted from social media sources. Three different publicly available datasets with varying number of attributes and records from tourism domain are used for the experiments conducted as part of this work","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"11 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75647695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.59025
Andriele da Silva Panosso, S. Paul
Assessing the acoustical performance of building floor systems relies on the impact source to be utilized and on the type of floor cover used. Besides that, a reliable assessment should consider the listeners’ judgments of the sounds transmitted through floors or radiated by them. Objective ratings measured can help to foresee tenant satisfaction provided that they are well correlated with the listeners’ judgments. The main objective of this study was to compare objective and subjective evaluations, using two types of impact sources and two types of floor covers, to try and determine which objective variables could be used to predict subject evaluation and to validate the use of an alternative impact source to be used in more realistic measurements. An objective evaluation was carried out employing impact noise insulation measurements according to ISO 10140:2010, evaluating different types of floors, resilient materials, and impact sound sources (a standardized tapping machine and a calibrated tire). In the analysis of the measured samples, several parameters were evaluated according to the sound source used. Simultaneously, "sound samples" were recorded to be used in a subjective evaluation based on the judgments of 29 listeners about the Noise Annoyance and the Loudness Sensation in response to the two impact sources. The magnitude estimation method was used. Results demonstrate that tapping machine measurements correlate very well with the subjective evaluation measurements and the calibrated tire presents well-correlated results in a specific measurement set-up. In addition, linear regression analysis of the objective and subjective variables shows alternative single number quantities for ratings of impact noise insulation
{"title":"Subjective evaluation of floor impact noise using the tapping machine and a non-standardized source","authors":"Andriele da Silva Panosso, S. Paul","doi":"10.4025/actascitechnol.v44i1.59025","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.59025","url":null,"abstract":"Assessing the acoustical performance of building floor systems relies on the impact source to be utilized and on the type of floor cover used. Besides that, a reliable assessment should consider the listeners’ judgments of the sounds transmitted through floors or radiated by them. Objective ratings measured can help to foresee tenant satisfaction provided that they are well correlated with the listeners’ judgments. The main objective of this study was to compare objective and subjective evaluations, using two types of impact sources and two types of floor covers, to try and determine which objective variables could be used to predict subject evaluation and to validate the use of an alternative impact source to be used in more realistic measurements. An objective evaluation was carried out employing impact noise insulation measurements according to ISO 10140:2010, evaluating different types of floors, resilient materials, and impact sound sources (a standardized tapping machine and a calibrated tire). In the analysis of the measured samples, several parameters were evaluated according to the sound source used. Simultaneously, \"sound samples\" were recorded to be used in a subjective evaluation based on the judgments of 29 listeners about the Noise Annoyance and the Loudness Sensation in response to the two impact sources. The magnitude estimation method was used. Results demonstrate that tapping machine measurements correlate very well with the subjective evaluation measurements and the calibrated tire presents well-correlated results in a specific measurement set-up. In addition, linear regression analysis of the objective and subjective variables shows alternative single number quantities for ratings of impact noise insulation","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"40 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78050893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.59244
J. Rocha, R. Magalhães, L. G. Carvalho, A. Diotto, B. Barbosa
Irrigation is a practice that increases productivity and enables the expansion of agricultural borders. This practice should be well managed to ensure the efficient use of water by plants, and such management requires specialized labor, which increases operating costs. Therefore, the main objective of this study is the implementation of an automated irrigation system that considers factors ranging from water demand to the operation of the system. Because the daily water demand is determined by crop evapotranspiration, a low-cost weather station was developed to acquire data daily. Such data can be used to estimate the reference evapotranspiration (ET0) using the Penman-Monteith model of the Food and Agriculture Organization (FAO). Thus, by combining the amount of water required by a crop with the physical and hydraulic properties of the soil and the hydraulic properties of the irrigation system, it was possible to determine the daily frequency and amount of time required for the system to operate to meet the water requirements of the crop without undergoing stress from a deficit or an excess of water. The management/monitoring system was designed and implemented to allow the user to access data remotely through an online application. This application enables the real-time transmission of irrigation-related data, such as weather station data and system logs, obviating the need for the user to be present at the crop site. This allows the supervision of many areas simultaneously with low cost
{"title":"Development of a low-cost weather station and real-time monitoring for automated irrigation management","authors":"J. Rocha, R. Magalhães, L. G. Carvalho, A. Diotto, B. Barbosa","doi":"10.4025/actascitechnol.v44i1.59244","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.59244","url":null,"abstract":"Irrigation is a practice that increases productivity and enables the expansion of agricultural borders. This practice should be well managed to ensure the efficient use of water by plants, and such management requires specialized labor, which increases operating costs. Therefore, the main objective of this study is the implementation of an automated irrigation system that considers factors ranging from water demand to the operation of the system. Because the daily water demand is determined by crop evapotranspiration, a low-cost weather station was developed to acquire data daily. Such data can be used to estimate the reference evapotranspiration (ET0) using the Penman-Monteith model of the Food and Agriculture Organization (FAO). Thus, by combining the amount of water required by a crop with the physical and hydraulic properties of the soil and the hydraulic properties of the irrigation system, it was possible to determine the daily frequency and amount of time required for the system to operate to meet the water requirements of the crop without undergoing stress from a deficit or an excess of water. The management/monitoring system was designed and implemented to allow the user to access data remotely through an online application. This application enables the real-time transmission of irrigation-related data, such as weather station data and system logs, obviating the need for the user to be present at the crop site. This allows the supervision of many areas simultaneously with low cost","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"131 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88733715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.26678/ABCM.ENCIT2018.CIT18-0481
L. Krambeck, Guilherme Antonio Bartmeyer, Diógenes Oliveira de Souza, D. Fusão, P. H. Santos, T. A. Alves
A selection of capillary structure of sintered copper powder for heat pipes based on the experimental thermal performance was conducted. Due to the geometric characteristics, the manufactured heat pipes can be used in electronics cooling. The heat pipes are used to enhance the heat transfer and are based on phase change. The sintered metal powder structures have a high capillary pumping, low pores, and good thermal conductivity. The heat pipes were manufactured from a straight copper pipe with an external diameter of 9.45mm, an inner diameter of 7.75mm, and a length of 200mm. The capillary structure was made of sintered copper powder with three different thicknesses (2.125mm, 1.500mm, and 0.875mm). Distilled water was used as the working fluid. Each thickness was analyzed with four different filling ratios related to the evaporator volume: 60, 80, 100, and 120%. The condenser was cooled by forced convection of air, the adiabatic section was insulated, and the evaporator was heated by an electrical resistor and was insulated from the environment with aeronautic insulation. The heat pipes were tested horizontally under different low heat loads (from 5 up to 45W). The experimental results showed that all sintered heat pipes worked satisfactorily. However, Type #3 Heat Pipe with a filling ratio of 100% showed the best thermal performance.
{"title":"Thickness Influence of the Copper Powder Sintered Capillary Structure in the Thermal Performance of Heat Pipes","authors":"L. Krambeck, Guilherme Antonio Bartmeyer, Diógenes Oliveira de Souza, D. Fusão, P. H. Santos, T. A. Alves","doi":"10.26678/ABCM.ENCIT2018.CIT18-0481","DOIUrl":"https://doi.org/10.26678/ABCM.ENCIT2018.CIT18-0481","url":null,"abstract":"A selection of capillary structure of sintered copper powder for heat pipes based on the experimental thermal performance was conducted. Due to the geometric characteristics, the manufactured heat pipes can be used in electronics cooling. The heat pipes are used to enhance the heat transfer and are based on phase change. The sintered metal powder structures have a high capillary pumping, low pores, and good thermal conductivity. The heat pipes were manufactured from a straight copper pipe with an external diameter of 9.45mm, an inner diameter of 7.75mm, and a length of 200mm. The capillary structure was made of sintered copper powder with three different thicknesses (2.125mm, 1.500mm, and 0.875mm). Distilled water was used as the working fluid. Each thickness was analyzed with four different filling ratios related to the evaporator volume: 60, 80, 100, and 120%. The condenser was cooled by forced convection of air, the adiabatic section was insulated, and the evaporator was heated by an electrical resistor and was insulated from the environment with aeronautic insulation. The heat pipes were tested horizontally under different low heat loads (from 5 up to 45W). The experimental results showed that all sintered heat pipes worked satisfactorily. However, Type #3 Heat Pipe with a filling ratio of 100% showed the best thermal performance.","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"9 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81508882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.57634
N. F. Shamsuddin, M. S. Mohktar, R. Rajasuriar, Safwani Wan Kamarul Zaman, Fatimah Ibrahim, A. Kamarulzaman
The purpose of this study is to analyses the relationship between fat mass and inflammation marker, interleukin-6, clinical and metabolic data in 71 human immunodeficiency virus (HIV)-positive male patients using bivariate linear regression analyses and artificial neural network. The data used consisted of measurements collected from HIV male subjects aged 26 to 69 years, with body mass index (BMI) values between 15.47 and 36.98 kg m-2 and the fat mass values between 1.00 kg and 16.70 kg. The bivariate linear regression analyses showed that weight, waist-hip ratio, BMI, triglycerides, high-density lipoprotein and HIV viral load value were significant risk factors associated with the body fat mass in male HIV patients. Furthermore, an in-depth non-linear analysis has been performed using artificial neural network (ANN) to predict fat mass by using the significant predictors as input. ANN model with four hidden neurons obtained the highest mean predictive accuracy percentage of 85.26%. The finding of this study is able to help with the evaluation of the fat mass in the male HIV patients that consequently reflects the patients metabolic-related irregularity and immune response. It is also believed that the outcome from the analysis can help future HIV-related study on the prediction of body fat mass in male HIV patients especially in settings where dual energy X-ray absorptiometry assessments, the standard measurement method for fat mass are not available or affordable
本研究旨在利用双变量线性回归分析和人工神经网络分析71例HIV阳性男性患者的脂肪量与炎症标志物、白细胞介素-6、临床和代谢数据的关系。所使用的数据包括从26至69岁的艾滋病毒男性受试者中收集的测量数据，体重指数(BMI)值在15.47至36.98 kg m-2之间，脂肪量值在1.00至16.70 kg之间。双变量线性回归分析显示，体重、腰臀比、BMI、甘油三酯、高密度脂蛋白和HIV病毒载量值是影响男性HIV患者体脂量的显著危险因素。此外，利用人工神经网络(ANN)进行了深入的非线性分析，以显著预测因子作为输入来预测脂肪量。4个隐藏神经元的ANN模型平均预测准确率最高，达到85.26%。本研究的发现能够帮助评估男性HIV患者的脂肪量，从而反映患者代谢相关的紊乱和免疫反应。我们还认为，分析结果可以帮助未来的HIV相关研究预测男性HIV患者的体脂量，特别是在双能x线吸收仪评估，脂肪量的标准测量方法无法获得或负担不起的情况下
{"title":"Analysis of fat mass value, clinical and metabolic data and interleukin-6 in HIV-positive males using regression analyses and artificial neural network","authors":"N. F. Shamsuddin, M. S. Mohktar, R. Rajasuriar, Safwani Wan Kamarul Zaman, Fatimah Ibrahim, A. Kamarulzaman","doi":"10.4025/actascitechnol.v44i1.57634","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.57634","url":null,"abstract":"The purpose of this study is to analyses the relationship between fat mass and inflammation marker, interleukin-6, clinical and metabolic data in 71 human immunodeficiency virus (HIV)-positive male patients using bivariate linear regression analyses and artificial neural network. The data used consisted of measurements collected from HIV male subjects aged 26 to 69 years, with body mass index (BMI) values between 15.47 and 36.98 kg m-2 and the fat mass values between 1.00 kg and 16.70 kg. The bivariate linear regression analyses showed that weight, waist-hip ratio, BMI, triglycerides, high-density lipoprotein and HIV viral load value were significant risk factors associated with the body fat mass in male HIV patients. Furthermore, an in-depth non-linear analysis has been performed using artificial neural network (ANN) to predict fat mass by using the significant predictors as input. ANN model with four hidden neurons obtained the highest mean predictive accuracy percentage of 85.26%. The finding of this study is able to help with the evaluation of the fat mass in the male HIV patients that consequently reflects the patients metabolic-related irregularity and immune response. It is also believed that the outcome from the analysis can help future HIV-related study on the prediction of body fat mass in male HIV patients especially in settings where dual energy X-ray absorptiometry assessments, the standard measurement method for fat mass are not available or affordable","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"39 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88205652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.58660
A. Piccini, G. C. Guimarães, A. C. Souza, Ana Maria Denardi, L. R. C. Silva, J. O. Rezende
With a great potential yet to be explored in Brazil, the grid-connected photovoltaic system, besides supplying the active power, can also contribute to improve the voltage level grid providing reactive power. Therefore, this work proposes to use a Grid-Connected Photovoltaic System (GCPVS) equipped with a control that uses the automatic voltage regulator (AVR) to balance the injection of the active and reactive powers, thus softening the short-duration voltage variation, more specifically the momentary voltage dip. For this purpose, the GCPVS was connected in part of a real distribution grid that attend the block 1106 South of Palmas city, state of Tocantins, northern region of Brazil. It is shown that the active and reactive power delivered to the grid can be controlled to help the power quality of the main grid during a disturbance. During a short-circuit situation, the active power is reduced, freeing up space from the inverter capacity for maximum supply of reactive power, in this way, helping the main grid to return to an adequate voltage level. The simulation results show that such voltage profile improvement is possible. Therefore, they confirm that photovoltaic systems, even though considered small, can also provide ancillary services to the low voltage distribution grid during abnormal conditions, adding to the actions normally performed by conventional power plants
{"title":"Grid-connected photovoltaic system to mitigate momentary voltage dip based on the balance between the active and reactive powers","authors":"A. Piccini, G. C. Guimarães, A. C. Souza, Ana Maria Denardi, L. R. C. Silva, J. O. Rezende","doi":"10.4025/actascitechnol.v44i1.58660","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.58660","url":null,"abstract":"With a great potential yet to be explored in Brazil, the grid-connected photovoltaic system, besides supplying the active power, can also contribute to improve the voltage level grid providing reactive power. Therefore, this work proposes to use a Grid-Connected Photovoltaic System (GCPVS) equipped with a control that uses the automatic voltage regulator (AVR) to balance the injection of the active and reactive powers, thus softening the short-duration voltage variation, more specifically the momentary voltage dip. For this purpose, the GCPVS was connected in part of a real distribution grid that attend the block 1106 South of Palmas city, state of Tocantins, northern region of Brazil. It is shown that the active and reactive power delivered to the grid can be controlled to help the power quality of the main grid during a disturbance. During a short-circuit situation, the active power is reduced, freeing up space from the inverter capacity for maximum supply of reactive power, in this way, helping the main grid to return to an adequate voltage level. The simulation results show that such voltage profile improvement is possible. Therefore, they confirm that photovoltaic systems, even though considered small, can also provide ancillary services to the low voltage distribution grid during abnormal conditions, adding to the actions normally performed by conventional power plants","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"2 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86959271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.58806
Denise Salvador de Souza, R. C. Valadão, Alexandre Lioi Nascentes, Leonardo Rafael da Silva, Henrique Vieira de Mendonça
In the present study, the microalga Spirulina platensis (Arthrospira) was grown in two horizontal photobioreactors (HPBR) under two different irradiances (150 and 270 μmol m-2 s-2). Anaerobically digested cattle wastewater (ACWW) was used as substrate. The experiment was carried out in batches for a period of 8 days. The maximum specific growth rate of 0.347 day-1 and the doubling time of 2.08 days were obtained under the highest illumination of the culture. Dry biomass production reached maximum values between 2.17 g L-1 and 6.52 g L-1, with volumetric biomass productivities between 0.0812 and 0.5578 g L-1 day-1. Productivity per area was equal to 47.97 g m-2 d-1, which is the highest value recorded compared to those found in the literature consulted. As for CO2 biofixation, relevant values for reducing this gas in the atmosphere were obtained, ranging from 128.52 to 882.36 mg L-1 day-1. In terms of organic matter, 16.3-77% of BOD5 and 12.6-61.6% of COD were reduced. In the reduction of TS, TSS and VSS, values of 71.3-78.5%, 79.5-84.4% and 87.0-88.3%, respectively, were reached. NH4+ reduction was 32.5-98.3%, organic nitrogen reduction was 20.3-95.9% and total phosphorus reduction was 33.5-89.9%. The reductions of thermotolerant coliforms were between 71.7% and 99.9%. In view of the results found, it can be considered that the bioremediation of the effluent reached promising efficiencies, with the advantage of producing biomass with potential to obtain bioproducts of relevant economic value
{"title":"Use of the cyanobacterium Spirulina platensis in cattle wastewater bioremediation","authors":"Denise Salvador de Souza, R. C. Valadão, Alexandre Lioi Nascentes, Leonardo Rafael da Silva, Henrique Vieira de Mendonça","doi":"10.4025/actascitechnol.v44i1.58806","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.58806","url":null,"abstract":"In the present study, the microalga Spirulina platensis (Arthrospira) was grown in two horizontal photobioreactors (HPBR) under two different irradiances (150 and 270 μmol m-2 s-2). Anaerobically digested cattle wastewater (ACWW) was used as substrate. The experiment was carried out in batches for a period of 8 days. The maximum specific growth rate of 0.347 day-1 and the doubling time of 2.08 days were obtained under the highest illumination of the culture. Dry biomass production reached maximum values between 2.17 g L-1 and 6.52 g L-1, with volumetric biomass productivities between 0.0812 and 0.5578 g L-1 day-1. Productivity per area was equal to 47.97 g m-2 d-1, which is the highest value recorded compared to those found in the literature consulted. As for CO2 biofixation, relevant values for reducing this gas in the atmosphere were obtained, ranging from 128.52 to 882.36 mg L-1 day-1. In terms of organic matter, 16.3-77% of BOD5 and 12.6-61.6% of COD were reduced. In the reduction of TS, TSS and VSS, values of 71.3-78.5%, 79.5-84.4% and 87.0-88.3%, respectively, were reached. NH4+ reduction was 32.5-98.3%, organic nitrogen reduction was 20.3-95.9% and total phosphorus reduction was 33.5-89.9%. The reductions of thermotolerant coliforms were between 71.7% and 99.9%. In view of the results found, it can be considered that the bioremediation of the effluent reached promising efficiencies, with the advantage of producing biomass with potential to obtain bioproducts of relevant economic value","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"34 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80850755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.57766
Mariene Marques Nolli, A. Contato, T. Brugnari, Ana Júlia dos Reis Buzzo, Guilherme Mauro Aranha, Fabíola Dorneles Inácio, R. Peralta, C. G. M. Souza
The study evaluated the production of proteases in solid-state fermentation using wheat bran as a substrate. The best producing isolates were used to obtain crude extract which was evaluated for optimal pH and temperature, thermostability, effect of salts and activity against inhibitors. The studied fungi were Aspergillus sp. 125, Fusarium sp. 132, Fusarium sp. 206, Pleurotus albidus 018 and Pleurotus pulmonarius CCB20. The isolates with better results (Aspergillus sp. and P. albidus), showed protease activity with an optimum pH of 7.0, and an optimum temperature of 50ºC with good thermostability between 40 and 50ºC. As for salts, the protease activity was inhibited in the presence of ZnSO4, and the activity of the proteases from the crude Aspergillus extract, strongly inhibited by PMSF, indicating the presence of a fraction of serine protease in the extract. The extracts of the two selected isolates showed considerable inhibition by EDTA. The milk clotting activity was 240 U mL-1 for the Aspergillus extract and 153 U mL-1 for the crude P. albidus extract. Proteases are important enzymes widely used in the food industry, including cheese. The data suggest that these fungi have the potential to produce these enzymes for usage in cheese making
该研究评估了以麦麸为底物的固态发酵蛋白酶的生产。对最佳产菌株进行了粗提液的筛选，并对粗提液的最佳pH、温度、热稳定性、盐的作用和对抑制剂的活性进行了评价。研究的真菌有曲霉125、镰刀菌132、镰刀菌206、白侧耳菇018和肺侧耳菇CCB20。结果表明，菌株(Aspergillus sp.和P. albidus)最适pH为7.0，最适温度为50℃，最适温度为40 ~ 50℃，具有较好的热稳定性。在盐类方面，ZnSO4对蛋白酶活性有抑制作用，PMSF对粗曲霉提取物蛋白酶活性有较强的抑制作用，说明粗曲霉提取物中存在部分丝氨酸蛋白酶。所选两株提取物对EDTA有明显的抑制作用。曲霉提取物的凝乳活性为240 U mL-1，粗粗白双曲提取物的凝乳活性为153 U mL-1。蛋白酶是一种重要的酶，广泛应用于食品工业，包括奶酪。数据表明，这些真菌有可能产生用于奶酪制作的这些酶
{"title":"Evaluation of the milk clotting potential and characterization of proteases from Aspergillus sp. and Pleurotus albidus","authors":"Mariene Marques Nolli, A. Contato, T. Brugnari, Ana Júlia dos Reis Buzzo, Guilherme Mauro Aranha, Fabíola Dorneles Inácio, R. Peralta, C. G. M. Souza","doi":"10.4025/actascitechnol.v44i1.57766","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.57766","url":null,"abstract":"The study evaluated the production of proteases in solid-state fermentation using wheat bran as a substrate. The best producing isolates were used to obtain crude extract which was evaluated for optimal pH and temperature, thermostability, effect of salts and activity against inhibitors. The studied fungi were Aspergillus sp. 125, Fusarium sp. 132, Fusarium sp. 206, Pleurotus albidus 018 and Pleurotus pulmonarius CCB20. The isolates with better results (Aspergillus sp. and P. albidus), showed protease activity with an optimum pH of 7.0, and an optimum temperature of 50ºC with good thermostability between 40 and 50ºC. As for salts, the protease activity was inhibited in the presence of ZnSO4, and the activity of the proteases from the crude Aspergillus extract, strongly inhibited by PMSF, indicating the presence of a fraction of serine protease in the extract. The extracts of the two selected isolates showed considerable inhibition by EDTA. The milk clotting activity was 240 U mL-1 for the Aspergillus extract and 153 U mL-1 for the crude P. albidus extract. Proteases are important enzymes widely used in the food industry, including cheese. The data suggest that these fungi have the potential to produce these enzymes for usage in cheese making","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"25 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80303477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-11DOI: 10.4025/actascitechnol.v44i1.57398
Bruno Benato Rutyna, M. A. Pinto, R. Neundorf, Márcio Alexandro Maciel de Anunciação, M. Martins
In this work, we applied different extrapolation techniques in association with the multigrid method to discover which one is the most effective in reducing the iteration error and the processing time (CPU time), as well as in improving the convergence factors. The mathematical model studied refers to the two-dimensional laminar flow of an isothermal time-dependent incompressible fluid modeled by the Navier-Stokes equations, with , solved iteratively with the projection method and the Finite Volume Method. The extrapolation methods used were: Aitken, Empiric, Mitin, scalar Epsilon, scalar Rho, topological Epsilon, and topological Rho. A two-step application was performed: first, extrapolators methods were applied individually after the use of the multigrid method. Then, the best-performing extrapolation techniques were used in the second step, where they were applied between the cycles of the multigrid method. The methods that presented the best convergence properties in the first stage were topological and scalar Epsilon. In the second stage, both methods maintained their performance, however, the topological Epsilon method presented more significant convergence rates than the scalar Epsilon. The other parameters analyzed were: the storage memory peak, the dimensionless norm of the residual based on the initial estimate, and the error norms of iteration. Thus, it was possible to state which extrapolation technique performed best and to compare it with the multigrid method with no extrapolation, which in this study was the topological Epsilon method.
{"title":"Measuring the effectiveness of extrapolation techniques associated with the multigrid method applied to the Navier-Stokes equations","authors":"Bruno Benato Rutyna, M. A. Pinto, R. Neundorf, Márcio Alexandro Maciel de Anunciação, M. Martins","doi":"10.4025/actascitechnol.v44i1.57398","DOIUrl":"https://doi.org/10.4025/actascitechnol.v44i1.57398","url":null,"abstract":"In this work, we applied different extrapolation techniques in association with the multigrid method to discover which one is the most effective in reducing the iteration error and the processing time (CPU time), as well as in improving the convergence factors. The mathematical model studied refers to the two-dimensional laminar flow of an isothermal time-dependent incompressible fluid modeled by the Navier-Stokes equations, with , solved iteratively with the projection method and the Finite Volume Method. The extrapolation methods used were: Aitken, Empiric, Mitin, scalar Epsilon, scalar Rho, topological Epsilon, and topological Rho. A two-step application was performed: first, extrapolators methods were applied individually after the use of the multigrid method. Then, the best-performing extrapolation techniques were used in the second step, where they were applied between the cycles of the multigrid method. The methods that presented the best convergence properties in the first stage were topological and scalar Epsilon. In the second stage, both methods maintained their performance, however, the topological Epsilon method presented more significant convergence rates than the scalar Epsilon. The other parameters analyzed were: the storage memory peak, the dimensionless norm of the residual based on the initial estimate, and the error norms of iteration. Thus, it was possible to state which extrapolation technique performed best and to compare it with the multigrid method with no extrapolation, which in this study was the topological Epsilon method.","PeriodicalId":7140,"journal":{"name":"Acta Scientiarum-technology","volume":"73 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77382242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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