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Treatment of swine wastewater using almond and cherry by-products as coagulants

In recent years, there has been a notable increase in the number of swine farms worldwide. This rise is primarily driven by the growing demand for protein sources, leading to a substantial generation of swine or piggery wastewater. This wastewater is characterized by a high concentration of ammonia, which possesses a considerable risk of eutrophication and adverse environmental effects [1]. Consequently, researchers have increasingly focused on investigating secure and effective approaches for treating and disposing of swine wastewater.

This industry generates large volumes of wastewater which contains a high quantity of suspended solids content, organic matter (BOD5 and COD), nutrients and fecal coliforms [2]. All these factors contribute to environmental degradation if it is discharged without proper treatment. Therefore, the aim of this work was the treatment of wastewater from swine farming using a coagulation-flocculation-decantation (CFD) process.

The CFD process was performed by organic coagulants derived from almond hull (AH) and cherry pit (CP). The CFD experiments were performed under a fast mix of 150 rpm/3 min and a slow mix of 20 rpm/20 min, at ambient temperature (25ºC). Four different coagulant concentrations were tested (0.1, 0.5, 1.0 and 2.0 g/L) and four different pH levels (3.0, 6.0, natural and 9.0). After sedimentation, samples were retrieved for analysis. The results showed that pH 3.0 allowed to achieve turbidity, total suspended solids (TSS) and chemical oxygen demand (COD) removals of 51.4, 67.3 and 15.9%, respectively, using AH coagulant. Regarding CP coagulant, the results showed that a pH of 3.0 achieved turbidity, TSS and COD removals of 55.0, 74.8 and 14.0% for SW. The variation of coagulant concentration was also assessed and the results showed that 0.1 g/L of AH achieved turbidity, TSS and COD removals of 43.3, 61.4 and 16.9%, respectively. The CP concentration of 0.1 g/L accomplished turbidity, TSS and COD removals of 61.7, 73.2 and 13.5%. Based on these results, the AH and CP were able to reduce the organic load of swine wastewater being its efficiency affected by the pH and coagulant concentration. The application of almond and cherry by-products as coagulants allowed to valorise the waste generated from these two food industries and, at the same time, treat the swine wastewater.

Acknowledgements

Authors acknowledge the OBTain project (NORTE-01-0145-FEDER-000084), co-financed by the European Regional Development Fund (ERDF) through NORTE 2020, and FCT for the financial support to CQVR (UIDB/00616/2020).

References

  1. Nagarajan, D., et al., Current advances in biological swine wastewater treatment using microalgae-based processes. PloS one, 2019. 289: 121718.
  2. Cheng, D.L., et al., Bioprocessing for elimination antibiotics and hormones from swine wastewater. Sci Total Environ, 2018. 621: 1664-1682.
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FORMULATION OF SELF-COMPACTING CONCRETE MIXTURES INCORPORATING DIVERSE CEMENT TYPES
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Self-Compacting Concrete (SCC) is a highly flowable, self-leveling and non-segregating type of concrete that requires no form of vibration to maintain its uniformity throughout the mixture as well as performs in an outstanding manner in densely reinforced structures. The properties of SCC such as cohesiveness, stability, flowability etc. can be modified by selecting definitive amounts of aggregates, cementitious materials and viscosity modifying admixtures.

The main objective of this study is to investigate the primary differences in engineering properties of SCC using CEM-I, CEM-II/A-M and CEM-II/B-M types of cement as primary binding material. It will also highlight the effects of mechanical and flow properties of the concrete mix due to the change in cement type with the similar composition and volumetric ratio of other constituent materials. The flow characteristics primarily rely on the cohesiveness of the mixture, making the addition of a superplasticizer highly advantageous in enhancing fluidity. However, the impact of additives may vary depending on the specific cement types utilized.

The necessary flow characteristics can be assessed through a sequence of tests, including the V-funnel test, L-box test, T-500 test, slump test, J-ring test, among others. Each of these test parameters possesses a specific range that must be satisfied by the concrete mix. After selecting the suitable mix design with CEM-I cement, wherein the flow values fall within the acceptable range, mix designs were subsequently prepared, maintaining a similar volumetric ratio of the constituent materials. The only variation in these designs was the type of cement used, and the corresponding strength properties i.e., compressive, tensile, and flexural strength were examined after a duration of 28 days. The variations and correlations among these values were then established and analyzed. Therefore, this study aims to provide valuable insights into the critical parameters necessary to achieve the ultimate strength capacities using both OPC and PCC cement types to meet the demands of real-life projects and seeks to identify cost-effective construction practices that could contribute to economic benefits.

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Physics-Based Approach to Deep Interseismic Creep: Implications for North Tabriz Fault Behavior Using MCMC

Many studies assume that the distribution of fault slip rate remains constant with time when examining surface deformation. However, recent numerical simulations have shown that dynamic rupture can penetrate regions with increased friction and diffuse from the lock-to-creep transition, contradicting this assumption. Bruhat and Segall (2017) introduced a new method to account for downward penetration of interseismic slip into the locked zone. This study builds upon their work by applying their model to strike-slip fault environments and incorporating creep coupling to viscoelastic flow in the lower crust and upper mantle. In this study using Bruhat's (2019) model, the interseismic deformation rates on the North Tabriz Fault are investigated. This study utilizes elastic and viscoelastic probabilistic models to fit horizontal surface rates. By employing this updated approach, a physics-based solution for deep interseismic creep is developed, revealing potential slow vertical propagation. The improved fit of horizontal deformation rates on the North Tabriz Fault is examined, leading to reasonable estimations of earthquake rupture depth and seismic displacement. The best-fit solutions suggest a half-space relaxation time of approximately 156 years, with a diffusion rate of less than 1 m/yr and around 0.419 m/yr, indicating minimal creep diffusion.

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Sensorless Speed Control of Induction Motor using Model Reference Adaptive System and Deadbeat Regulator

This paper presents the sensorless speed control of induction motors utilizing the Model Reference Adaptive System (MRAS) method and field-oriented control. The core objective is to minimize the cost related to speed sensors, thereby improving both the affordability and efficiency of motor control. Elimination of the sensor is achieved by estimating the rotor's angular speed, and the MRAS approach offers a sturdy alternative for this purpose. The presented approach provides a robust alternative, where the adaptation mechanism is facilitated by the implementation of a Deadbeat regulator. This mechanism allows for an improved response and superior control in motor operations, thus making sensor-based systems less necessary. In order to ascertain the efficiency of the proposed method, a comprehensive simulation test was conducted using MATLAB/Simulink.

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Irradiated Hazelnut (Corylus avellana): Identification and Dose Assessment Using EPR
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Food irradiation aims to eliminate biohazards such as pathogens, microbes, fungi, etc. identification of irradiated food and dose assessment ensures its safe use. Hazelnut is the most universal widespread nut and can be found as a whole fruit or as an ingredient in many food types. Electron paramagnetic resonance (EPR) was used to identify irradiated hazelnut and to assess radiation doses delivered to it using fractions of its kernel and shells. In this paper, parameters affecting the proper detection and evaluation of irradiated hazelnut kernels and shells are studied and analyzed including the response to Cs-137 gamma rays, effect of the change in microwave power and modulation amplitude values during EPR spectra acquisition. Stability study of the radiation-induced radicals suggests that it is better to perform EPR measurements for irradiated hazelnut during the first month following irradiation.

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Cytotoxic Activity of Metal Nanoparticle Complexes
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Published: 26 October 2023 by MDPI in 4th International Electronic Conference on Applied Sciences session Poster Session

Metal complexes are widely used in pharmaceutics, cosmetics, electronics, casting printing, and power generation. One of the major challenges due to their long-term use as medicines is their accumulation in the body. This issue needs to be resolved to avail better results of metal complexes as medicines. The use of metal-nanoparticles(MNPs) can be expected to reduce the toxicity of metal and their accumulation in the body. The aim of this paper is to give an insight about the variation induced in the cytotoxic activity of MNP-ligand complexes by replacing respecting heavy metals with their nanoparticles(NPs).

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Optimization of synthetic conditions for the preparation of core-shell structures of CdTe/ZnSe QDs in water

Quantum Dots (QDs) are nanocrystals of semiconductor materials that, when entered into a quantum confinement regime, feature unique optical properties. Because they are nanometric structures (2-10 nm), they have high density of dangling bonds on their surface, causing surface defects that can compromise their fluorescent properties. The superficial modification of QDs with layers from another semiconductor is an alternative to reduce these surface defects. In the present study, CdTe QDs were synthesized in an aqueous system, and subjected to different coating approaches with the ZnSe semiconductor, aiming for a core-shell heterostructure. Two QDs with different stabilizers were used: mercaptusuccinic acid (MSA) and cysteamine (CYA). Some experimental parameters were evaluated to coat these QDs with ZnSe (by controlled precipitation in a colloidal aqueous medium), such as the molar ratio of precursors, pH, reaction temperature, and the volume/frequency addition of precursors to the reaction medium. The absorption and emission spectra of all systems were analyzed before and after their modification. In general, it was observed that for CdTe-MSA, it was seen that the coating at room temperature (~ 30 ° C), at pH ~ 10.5 and with the addition of the precursors divided into five portions, was the best synthesis condition for the best response sought. It was obtained a photoluminescence improvement greater than 300%, with small spectral change. However, for CdTe-CYA QDs the emission enhancement was much lower, around 55%. Thus, this study reinforces the importance of studying the experimental conditions to control the surface modification process of QDs for an optimized emission.

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Advancing Towards a Circular Economy in the Textile Industry
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The textile and garment manufacturing process in the textile industry produces a significant amount of waste, including fabric scraps, dyes, chemicals, as well as leftover fibers and yarns, leading to environmental pollution. The issue of fabric and garment waste is a major concern within the industry. This review provides an overview of the prevailing waste challenges in the textile sector while exploring the basics of the circular economy. In addition, the current life cycle and a comprehensive system map are used to visualize the entire life cycle, with a particular focus on waste management and its environmental and social impacts. In alignment with circular economy principles, an alternative circular product proposal is presented. A second map illustrates the new proposition, highlighting its projected life cycle and points of impact. The review incorporates additional findings and relevant research related to these proposals, aiming to promote sustainable solutions for waste reduction in the textile industry.

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A Novel Quality Assessment Method for the Clinical Reproduction of Orthodontic Attachments based on Differential Entropy

In this study, the effectiveness of an experimental clinical technique of reproduction of attachments during an orthodontic treatment with clear aligners was evaluated using a new index (CorAl) for quality assessment that exploits the differential entropy of point clouds. The procedure involves the use of a pre-drilled template and a second pre-loaded template with high viscosity composite and is compared with the standard technique.

Attachment planning was conducted on four prototypes of dental arches with extracted teeth which were divided into two groups according to the proposed operating procedures. Digital scans were utilized to capture dental impressions for both the purposes of virtual planning and to reproduce the clinical outcomes post-procedure. The point clouds obtained after the reproduction of the attachments were aligned with those from the virtual planning, and the deviation analysis was conducted using the quality index of the CorAl method.

Though no significant discrepancies were found among the groups regarding morphological flaws, detachments, or maximum defect values, the differential entropy analysis revealed that the experimental technique offers good alignment in attachments placement.

The outcome supports that the innovative procedure of clinical reproduction of attachments proved to be reliable and operationally simple, with additional benefits derived from using the CorAl index. Advantages of CorAl include the use of a single comparison index, no problem of comparison commutativity, noise immunity, low influence from the presence of holes and point cloud densities. This allows for the drawing of quality maps that show areas with the highest deviation.

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A Comprehensive Comparison of Hargreaves Isothermal Model with Schmidt Model for the Gamma Stirling Engine

The Stirling engine, a type of external-combustion engine utilizing a compressible fluid as its working medium, holds promise as a highly efficient device for converting heat into mechanical work at Carnot efficiency. This research conducts a detailed analysis, comparing the Hargreaves isothermal model and the Schmidt model specifically for the gamma type Stirling engine. The study examines the impact of dead volume on the engine's performance, revealing that the engine network is solely influenced by these volumes. Furthermore, it highlights the effectiveness of Hargreaves model for the performance analysis of gamma type Stirling engines.

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