Multitrajectory Model Predictive Control for Safe UAV Navigation in an Unknown Environment

The problem of navigating an unmanned aerial vehicle (UAV) in an unknown environment is addressed with a novel model predictive control (MPC) formulation, named multitrajectory MPC (mt-MPC). The objective is to safely drive the vehicle to the desired target location by relying only on the partial description of the surroundings provided by an exteroceptive sensor. This information results in time-varying constraints during the navigation among obstacles. The proposed mt-MPC generates a sequence of position set points that are fed to control loops at lower hierarchical levels. To do so, the mt-MPC predicts two different state trajectories, a safe one and an exploiting one, in the same finite horizon optimal control problem (FHOCP). This formulation, particularly suitable for problems with uncertain time-varying constraints, allows one to partially decouple constraint satisfaction (safety) from cost function minimization (exploitation). Uncertainty due to modeling errors and sensors noise is taken into account as well, in a set membership (SM) framework. Theoretical guarantees of persistent obstacle avoidance are derived under suitable assumptions, and the approach is demonstrated experimentally out-of-the-laboratory on a prototype built with off-the-shelf components

Sustainability indicators in cooperative management of recyclable materials

Following the promulgation of the National Solid Waste Policy in 2010, legal provisions, government programs and sectoral agreements have been implemented, but without the expected efficiency in relation to recycling. It should be noted that Cooperatives of Recyclable Material Pickers (CRMP) should play a leading role in this regard, but they do not have adequate management to be economically, socially and environmentally sustainable, depending on assistance to maintain the activity. Aiming to elucidate this issue, in this paper was made an institutional diagnosis of the category of waste pickers using the Gramacho region in the city of Duque de Caxias (Rio de Janeiro) as a case study. It was carried out an evaluation of the historical context of the neighbourhood, and it was drawn up a semi-structured questionnaire in 12 of the 18 cooperatives in the region. The data were interpreted through a SWOT matrix and the Venn diagram. A matrix was proposed and elaborated with 15 sustainability indicators specific to the CRMC reality in order to evaluate and monitor the management of cooperatives. After collecting the primary data, it was possible to validate the matrix of indicators with indexes of cultural, economic, political and ecological sustainability of the cooperatives. It was found that the matrix of indicators facilitated the understanding of the data and the comparison between the indicators. This tool can help decision-making, creation of action plans and identification of demands by the cooperative waste pickers themselves, without the presence of an analyst or technician

Response surface for biodiesel production from soybean oil by ethylic route

Petroleum has been the most consumed energy source in the world, but it tends to run out due its non-renewable character. Among biofuels, biodiesel has emerged as the main candidate to substitute petroleum diesel. The present study aimed to identify the maximum yield point of biodiesel production by generating a response surface using molar ratio, temperature and agitation time as independent variables, and yield as a dependent variable. From the response surface, it is observed that the increase in temperature and reaction time leads to reduced yield. The configuration that resulted in maximum yield of 93.30% was 12:1 molar ratio, 30 °C temperature and 30-minute reaction time. From the chromatographic analysis it was possible to identify five different fatty acids in the composition of the biodiesels. Total saturated fatty acids (palmitic and stearic acids) ranged from 41.53% to 42.09% and total unsaturated fatty acids including monounsaturated and polyunsaturated fatty acids (oleic, linoleic and linolenic acids) ranged from 57.92% to 58.48%. According to the results of the physicochemical analyses, the specific mass at 68°F is in agreement with Brazilian, American and European specifications, ranging from 877.46 kg m-3 to 879.64 kg m-3 . The kinematic viscosity at 104 °F ranged from 4.49 mm² s -1 to 4.82 mm² s -1 . The acid value obtained did not vary within the limits established by the norms, and values between 0.54 and 2.74 mg KOH g -1 were observed

Forensic applications of micro-computed tomography: a systematic review

Purpose: The aim of this systematic review was to provide a comprehensive overview of micro-CT current applications in forensic pathology, anthropology, odontology, and neonatology. Methods: A bibliographic research on the electronic databases Pubmed and Scopus was conducted in the time frame 01/01/2001–31/12/2021 without any language restrictions and applying the following free-text search strategy: “(micro-computed tomography OR micro-CT) AND (forensic OR legal)”. The following inclusion criteria were used: (A) English language; (B) Application of micro-CT to biological and/or non-biological materials to address at least one forensic issue (e.g., age estimation, identification of post-mortem interval). The papers selected by three independent investigators have been then classified according to the investigated materials. Results: The bibliographic search provided 651 records, duplicates excluded. After screening for title and/or abstracts, according to criteria A and B, 157 full-text papers were evaluated for eligibility. Ninety-three papers, mostly (64) published between 2017 and 2021, were included; considering that two papers investigated several materials, an overall amount of 99 classifiable items was counted when referring to the materials investigated. It emerged that bones and cartilages (54.55%), followed by teeth (13.13%), were the most frequently analyzed materials. Moreover, micro-CT allowed the collection of structural, qualitative and/or quantitative information also for soft tissues, fetuses, insects, and foreign materials. Conclusion: Forensic applications of micro-CT progressively increased in the last 5 years with very promising results. According to this evidence, we might expect in the near future a shift of its use from research purposes to clinical forensic cases

Productive efficiency and density and viscosity studies of biodiesels from vegetable oil mixtures

Received: January 31st, 2021 ; Accepted: April 10th, 2021 ; Published: April 29th, 2021 ; Correspondence: [email protected] in Brazil the minimum content of biodiesel in mixtures is 11% and, according to Brazilian laws, the goal is to reach 15% in volume in diesel fuel available for final consumers by 2023. Therefore, studies about different matrices of biodiesel and distinct mixtures are essential. The present work had two goals, the first one was to analyse physico-chemical properties of 16 biofuels produced from soybean and cotton oils, using S10 diesel, in mixtures B8, B10, B20 and B30. The second goal was to verify the vantages and disadvantages of biodiesel production through prior mixing of the oils, before and after the transesterification process. All biofuels produced presented results of specific mass values at 20 °C and kinematic viscosity at 40 °C within the limits established by ANP Resolution no 30/2016 and International Resolutions. The soybean B20 biofuel showed the best overall results, with the second highest production yield of 65.36%, the fifth lowest kinematic viscosity with 3.48 mm s -1 . The mixture of soybean and cotton oils before the transesterification process presented the highest production yield when compared with the production from a single oil or biodiesel mixtures. The results found proved to be satisfactory and corroborate to continue with the increase of biodiesel in the mixture with diesel to B15 until 2023 and support the possibility of planning for a gradual increase of this mixture in the following years

PET/MRI in prostate cancer: a systematic review and meta-analysis

Aim: In recent years, the clinical availability of scanners for integrated positron emission tomography (PET) and magnetic resonance imaging (MRI) has enabled the practical potential of multimodal, combined metabolic-receptor, anatomical, and functional imaging to be explored. The present systematic review and meta-analysis summarize the diagnostic information provided by PET/MRI in patients with prostate cancer (PCa). Materials and methods: A literature search was conducted in three different databases. The terms used were \u201ccholine\u201d or \u201cprostate-specific membrane antigen - PSMA\u201d AND \u201cprostate cancer\u201d or \u201cprostate\u201d AND \u201cPET/MRI\u201d or \u201cPET MRI\u201d or \u201cPET-MRI\u201d or \u201cpositron emission tomography/magnetic resonance imaging.\u201d All relevant records identified were combined, and the full texts were retrieved. Reports were excluded if (1) they did not consider hybrid PET/MRI; or (2) the sample size was < 10 patients; or (3) the raw data were not enough to enable the completion of a 2 7 2 contingency table. Results: Fifty articles were eligible for systematic review, and 23 for meta-analysis. The pooled data concerned 2104 patients. Initial disease staging was the main indication for PET/MRI in 24 studies. Radiolabeled PSMA was the tracer most frequently used. In primary tumors, the pooled sensitivity for the patient-based analysis was 94.9%. At restaging, the pooled detection rate was 80.9% and was higher for radiolabeled PSMA than for choline (81.8% and 77.3%, respectively). Conclusions: PET/MRI proved highly sensitive in detecting primary PCa, with a high detection rate for recurrent disease, particularly when radiolabeled PSMA was used

Compost barn system and its influence on the environment, comfort and welfare of dairy cattle

Received: January 16th, 2023 ; Accepted: April 27th, 2023 ; Published: May 15th, 2023 ; Correspondence: [email protected] aim of this study was to evaluate the effect of the thermal environment on behavioral and physiological parameters of crossbred cows of different productivity levels confined in a compost barn system. For this, air temperature (Tdb) and relative humidity (RH) data were measured using sensors/registers and wind speed (Vair) was recorded with the aid of an anemometer. Subsequently, these data were used to calculate the Temperature and Humidity Index (THI). Bedding material variables (pH and humidity) were also evaluated. The animals were evaluated for physiological variables (respiratory rate – RR and surface temperature – ST), scores (body condition, locomotion and dirt) and behavior. The analyses were carried out on two groups of cows (Group 1: high production vs. Group 2: medium and low production). The average pH of the bedding material was 8.5, within the recommended range. In the case of the physiological responses of the cows, the respiratory rate (RR) of Group 1 indicated better conditions of thermal comfort in the morning vs. the afternoon. The system was efficient in both groups based on body condition score, indicating favorable conditions for the health of the animals. Regarding the behavioral evaluation, Group 1 and 2 were statistically similar and had the longest rumination times, in relation to the other evaluated behaviors. Regarding active periods, medium production were the most active. Regarding idle time, low production spent more time idle than the other animals

Acoustic analysis of cement composites with lignocellulosic residues

Received: January 19th, 2021 ; Accepted: May 20th, 2021 ; Published: October 5th, 2021 ; Correspondence: [email protected] concept of environmental sustainability has been seeking a way to develop projects that reduce the impacts provided by agricultural development and the excessive consumption of natural resources. However, there is still little knowledge about the acoustic insulation/absorption behaviour of lignocellulosic materials. Hence, this study aimed to evaluate the acoustic properties of five cement panels reinforced with the following lignocellulosic materials: eucalyptus, sugarcane bagasse, coconut shell, coffee husk, and banana pseudostem, which ones have as a reference a commercial plaster used as sealing in civil constructions. The proposed panels were produced with each lignocellulosic material residue. It was produced three replicates for each type including plaster (being 18 panels in total). The sound insertion loss (SIL) measurement of the above-mentioned panels have been performed using an acoustical treated inexpensive facility developed based on the literature. The characterization of the acoustic behaviour of the studied materials were analysed according to the IEC (61260-1). The acoustic measurements have been done in the range of 20 Hz to 20 kHz and the analysis in octave bands have been performed. To make the analysis easier, the overall range of frequencies mentioned above was divided as ‘low’, ‘middle’ and ‘high’ ranges. Additionally, the measurement of thickness, density and porosity structure parameters of the lignocellulosic samples have been performed. According to the results and doing a trade-off analysis, the eucalyptus presented the overall best performance considering the overall range of analysis, being the banana pseudostem and sugarcane bagasse materials as good competitors

18F-choline PET/CT and PET/MRI in primary and recurrent hyperparathyroidism: a systematic review of the literature

The aims of the present systematic review were to: (1) assess the role of 18F-fluorocholine (FCH) positron emission tomography (PET) with computed tomography (CT) and PET with magnetic resonance imaging (MRI) in patients with biochemically known hyperparathyroidism; (2) compare the diagnostic performance of FCH PET/CT or PET/MRI with conventional morphological and functional imaging. A literature search until December 2019 was performed in the PubMed, Scopus and Web of Science databases, using the terms “choline” AND “PET” AND “hyperparathyroidism”. The search was conducted with and without the addition of filters (e.g., language: English only; type of article: original article; subjects: humans only) and selecting only articles published in the last 5 years. Twenty-three articles and 1112 patients were considered. Different FCH PET/CT acquisition protocols were adopted across the studies, using dynamic, early or delayed scans. FCH PET/CT proved more accurate than ultrasonography (US) or 99mTc-sestamibi single-photon emission tomography (SPET). PET/MRI also seemed to be more accurate than MRI alone in detecting benign parathyroid lesions. FCH PET/CT is more accurate than conventional morphological and functional imaging modalities (US or SPET) for the detection of benign parathyroid lesions. It could, therefore, be a reliable tool in both primary and recurrent hyperparathyroidism

Comparison between the thermal properties of cement composites using infrared thermal images

The use of agribusiness residual lignocellulosic fibres can be a good alternative in the development of lignocellulosic composites. The current work aimed to investigate the thermal performance of cement-based composites with lignocellulosic materials: Eucalyptus, sugarcane bagasse, coconut fibre in comparison with commercial gypsum board to be used as internal partitions of the building using infrared thermal images. Three repetitions for each kind of lignocellulosic material were made, and three commercial gypsum boards were used. In the production of the panels, the following parameters were applied: material and cement ratio, 1:2.75; water and cement ratio, 1:2.5; hydration water rate of 0.25; additive, 4% (based on cement mass). The calculations were performed for a nominal panel density of 1,200 kg m- ³. The thermal analysis was performed in a chamber composed of MDP (Medium-Density Particleboard) and with an internal layer of rock wool and the heat source (thermal resistance). For the superficial temperature measurement, a FLIR E75 camera was used to capture the infrared images. When the internal temperature of the chamber stabilized at 50 °C, an infrared thermal image was collected from each side of the composite. Thermal properties were analysed: thermal conductivity, resistivity, resistance, and transmittance. Based on the results, sugar cane cement composites were characterized by higher values of thermal conductivity. Related to thermal resistivity, thermal resistance, and thermal transmittance, only the coconut panel presented similar behaviour to the commercial gypsum board. Thus, cement composite using coconut can be a potential alternative that might solve energy and environmental concerns simultaneously