A general review of power quality standards and terminologies

In the next few years, more than 80% of AC power is to be processed through power converters owing to their benefits of energy conservation, flexibility, network interconnection, and weight and volume reduction in a number of equipment such as lighting arrestors, HVAC computers, fans, and so on.This paper gives an introduction on power quality (PQ), causes and effects of power quality problems. It also deals with power quality definitions, terminologies, standards, bench-marks, monitoring requirements, financial loss, and analytical quantification. It also discusses various types of nonlinear loads, which cause these power quality problems, they are illustrated, classified, modeled, quantified, and analyzed forassociated power quality issues.

Challenges Ahead for a Rational Analysis of Vitamin D in Athletes

Vitamin D is an essential vitamin for the normal formation of bones and calcium absorption. It is synthesized into our body through sunlight exposure and obtained by consuming foods rich in vitamin D (e.g., fatty fish, eggs yolk, dairy products). Its benefits on the health and performance of athletes are well documented. This article outlines some analytical challenges concerning the analytical quantification of vitamin D for its optimal intake, namely, a comprehensive study of the variability of the assay before categorizing any method as the golden standard, assurance of sample comparability to draw meaningful correlations, revision of the intake guidance based on appropriate statistical power analysis, and the implementation of rational strategies for preventing the underlying mechanism of preanalytical factors. Addressing these challenges will enable the effective management of vitamin D in the sports sector.

A general review of power quality standards and terminologies

In the next few years, more than 80% of AC power is to be processed through power converters owing to their benefits of energy conservation, flexibility, network interconnection, and weight and volume reduction in a number of equipment such as lighting arrestors, HVAC computers, fans, and so on. This paper gives an introduction on power quality (PQ), causes and effects of power quality problems. It also deals with power quality definitions, terminologies, standards, bench- marks, monitoring requirements, financial loss, and analytical quantification. It also discusses various types of nonlinear loads, which cause these power quality problems, they are illustrated, classified, modeled, quantified, and analyzed for associated power quality issues.

Non-Slender n-Link Chain Driven by Single-Joint and Multi-joint Muscle Actuators: Closed-Form Dynamic Equations and Joint Reaction Forces

The author has derived the closed-form dynamic equations for a planar musculoskeletal chain composed of a generic number n of rigid links connected by ideal revolute joints. Single-joint and multi-joint muscles have been modeled as linear force actuators that can span from one joint to all the joints of the chain. The generic shape and size of each individual link of the chain accounts for different alignments among the center of mass of the link, the centers of rotation of the joints that articulate the link with its neighbors, and the points of application of the muscle forces and the possible contact external resistances acting on the link. The joint torque and the reaction force acting on each joint have been determined in closed-form by analytical quantification of the unique contribution of each individual kinematic and kinetic variable: (1) force of each single-joint or multi-joint muscle spanning or non-spanning the joint; (2) weight and contact external resistances acting on each individual link of the chain; (3) position, angular velocity, and angular acceleration of each individual link of the chain. The analytical results derived in this study can be applied to multilink musculoskeletal chains with deep/superficial and segmental/global muscles.

Potential Impact of Microplastics and Additives on the Health Status of Loggerhead Turtles (Caretta caretta) Stranded Along the Central Adriatic Coast

Loggerhead sea turtle (C. caretta) is the official European bioindicator of marine litter in the Mediterranean Sea. In 2019, 8 sea turtles, out of 28 specimens loggerhead on the Adriatic coast of Molise, were subjected to necropsy. The intestinal contents were collected and the microplastics until 0.45 μm were extracted. Qualitative and quantitative assessments were performed by stereomicroscope observation and spectroscopic analyses (attenuated total reflection-Fourier transform infrared spectroscopy, ATR-FTIR and Raman microspectroscopy, RMS). Moreover, the analytical quantification of polyethylene terephthalate (PET), polycarbonate (PC), para phthalic acid (PTA) and bisphenol A (BPA) in fat and liver tissues was performed by LC-MS/MS. Microparticles ranging from 0.45 μm to 1 mm were found in all turtles, for a total of 623, while plastic litter greater than 1 mm were found only in 4 specimens (ranging from 0.03 to 0.11 g). Nineteen different polymers and 10 pigments, including polyester (100% of animals), high-density polyethylene (50%) and polypropylene (50%) were identified. BPA, PTA and PET were detected in fat and liver tissues of all animals, while PC was found only in 50%. A major prevalence was registered in the abdominal fat tissue, although only PC compounds were significantly higher in abdominal tissue (p < 0.05), except for free PTA with liver tissue being the most contaminated (p < 0.05). Microplastics and additives surely impact the health status of turtles that showed gastrointestinal impairment and an important level of contamination in tissues. Graphical abstract

The Use of a Micro Near Infrared Portable Instrument to Predict Bioactive Compounds in a Wild Harvested Fruit—Kakadu Plum (Terminalia ferdinandiana)

Kakadu plum (KP; Terminalia ferdinandiana Exell, Combretaceae) is an emergent indigenous fruit originating from Northern Australia, with valuable health and nutritional characteristics and properties (e.g., high levels of vitamin C and ellagic acid). In recent years, the utilization of handheld NIR instruments has allowed for the in situ quantification of a wide range of bioactive compounds in fruit and vegetables. The objective of this study was to evaluate the ability of a handheld NIR spectrophotometer to measure vitamin C and ellagic acid in wild harvested KP fruit samples. Whole and pureed fruit samples were collected from two locations in the Kimberley region (Western Australia, Australia) and were analysed using both reference and NIR methods. The standard error in cross validation (SECV) and the residual predictive deviation (RPD) values were 1.81% dry matter (DM) with an RPD of 2.1, and 3.8 mg g−1 DM with an RPD of 1.9 for the prediction of vitamin C and ellagic acid, respectively, in whole KP fruit. The SECV and RPD values were 1.73% DM with an RPD of 2.2, and 5.6 mg g−1 DM with an RPD of 1.3 for the prediction of vitamin C and ellagic acid, respectively, in powdered KP samples. The results of this study demonstrated the ability of a handheld NIR instrument to predict vitamin C and ellagic acid in whole and pureed KP fruit samples. Although the RPD values obtained were not considered adequate to quantify these bioactive compounds (e.g., analytical quantification), this technique can be used as a rapid tool to screen vitamin C in KP fruit samples for high and low quality vitamin C.

ANALYTICAL QUANTIFICATION OF STRESSES IN HYPERBOLIC COOLING TOWERS, UNDER ASYMMETRIC WIND LOADING ACTION

The objective of this work is to evaluate the wind stresses in hyperbolic cooling towers. These non-symmetrical efforts are of the utmost importance, as they usually govern the design of such structures. The main loading case for natural projects of reinforced concrete cooling towers is produced by forces from the wind, except in cases where forces generated by the action of earthquakes are considered.