At young ages the spinal column, which is the central support system of the human body, is susceptible to malformations, especially if the children are sitting in an incorrect position for long period. Our study examines the case of several elementary school students from a developed rural area. The aim of this study to analyze the impact of long sitting hours (5-6 hours) in incorrect position at on the normal standing up position at elementary school students. The study group for our study consisted of 80 elementary school students were recruited from a local rural elementary school. Each student was evaluated using a Kinect based system to determine their general standing up position. For 14 weeks, twice a week, each student has executed 5 type of Schroth exercises to improve their general body position. The first evaluation has shown that the students general standing up position is affected from the long sitting hours in the school benches. Most of them have shown misalignments at the shoulder and hip levels. In many cases one of the shoulders was higher than the other and the same is true for the hips as well. After 14 weeks of physiotherapy based on Schroth exercises the miss alignments were reduced to a bare minim. The results have shown that long sitting hours in incorrect positions can affect the spinal column and the standing up posture of the human body. In many cases malicious postures start to develop from childhood. If not treated they can transform in hyper-kyphotic and scoliotic postures which can induce other complications. If these malicious postures are observed in early stages of the children and with only 2 hours a week of physiotherapy based on Schroth exercise the postures can be corrected and the hyper-kyphotic and scoliotic postures can be avoided.
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Finite element analysis is the most commonly used methods in orthopedic biomechanical research. The study aims at improving the common understanding of the behavior of the pelvis and the biomechanics of the pelvic ring in a healthy and osteoporosis configuration. We performed a finite element analysis using the ANSYS program. The study mainly focused on bones and the joints and the complex modelling of the ligaments was ignored. The results of our study showed that the stress distribution of the pelvis with osteoporosis was changed compared with normal pelvis. In addition to, in the healthy bone, where the maximum stress values are concentrated around the obturator foramen (anterior arch of the pelvic ring), in the osteoporotic bone, the maximum stress also appear at the posterior arch of the pelvic ring (especially in the sacrum.
The topic of this paper refers to the influence of the plasticizer and the processing mode upon the characteristics of the poly(vinyl chloride) (PVC) composites. Thereby, in this study two types of industrial plasticizers were used to highlight their influence upon the properties of final composites. The employed lubricant was stearic acid, the most common and cheapest additive used in the industry for cables manufacturing. For economic reasons, calcium carbonate of 2 m size was used as reinforcing agent. Further on, two sets of samples were prepared, targeting the influence of the processing mode upon the properties of final composites. Beside the structure (by FT-infrared), thermal behavior (thermal analyses and differential scanning calorimetry) and mechanical properties (dynamic mechanical analyses, tensile strength and elongation at break) of PVC composites, the limiting oxygen index (LOI) and the overall morphology of the samples were also investigated.
Our study’s goal was to underline the differences between the girls’ and the boys’ representative in terms of age, in what concerns the moving speed and the effort perception during the dynamic balance when walking on the slackline throughout the activities specific for the Development through Education and Adventure (DEA). The results have shown the fact that the boys have a better speed movement on the slackline rather than the girls, allowing us to conclude that the boys’ dynamic balance is superior to the girls’ balance on both studied age categories. Perceiving the physical effort through heart rate is different according to age category when walking on the slackline for the groups of the study.
The main goal of this research study was to understand the role of the vegetable oil in the obtaining process of nanoparticles by emulsion solvent evaporation method, respectively the effect of the vegetable oil upon the final characteristics of hybrid PLGA-pomegranate vegetable oil (PMG) nanoparticles. Colloids with mean diameter around 125.6 nm (PLGA-np) and 141.7 nm (PLGA-PMG-np) were obtained. It was noted that the addition of the vegetable oil has a key role in the primary emulsification process leading to hybrid colloids with improved the uniformity (PdI) and stability of hybrid nanoparticles.
Ephedrine is an illicit drug, classified as precursor for methamphetamine, which is also used as stimulant, appetite suppressant, decongestant or asthma. In this study, novel molecularly imprinted polymer (MIP) films were prepared by sol-gel derived techniques, using N-(2-aminoethyl)-3-aminopropyltrimethoxysilane as functional monomer, to recognize ephedrine from aqueous solutions. The films were obtained by air-spraying the precursor solutions, with various concentrations of monomer and template, on glass supports. Infrared, thermogravimetry, ellipsometry, optic and atomic force microscopy analyzes of films provided information regarding the effect of molecular imprinting upon the physical properties of films. Further on, batch rebinding evaluation indicated that thinner films present high affinity for ephedrine, resulting in 6.2 imprinting factor after 15 minutes of contact, which attests the ability of the novel MIP films to recognize and rebind ephedrine.
In this study a fluid elastomer was applied by two different methods on a martensitic stainless steel substrate, in order to obtain coatings for protection against cavitation. The investigations regarding the resistance to cavitation erosion of the elastomeric coatings were carried out by the indirect vibratory method using the values of the cumulative erosion (material loss) developed during a testing period of 600 minutes with a 20 kHz ultrasonic vibrator at a peak-to-peak amplitude of 50 μm. The experimental results obtained in the laboratory have been processed statistically. They clearly pointed out that the deposition method significantly influences the cavitation resistance of the elastomer.
This paper describes a hip implant model designed to assess the Fused Deposition Modeling (FDM) process for manufacturing investment casting master patterns. In addition, an indirect approach toward manufacturing master pattern via silicone rubber moulding in conjunction with 3D Printing process manufactured hip implant master pattern has been investigated. The dimensional accuracies of the manufactured AM master patterns and the wax pattern are presented. Finally, cost and lead time comparisons carried out between FDM ABS pattern manufacturing, indirect pattern manufacturing via silicone rubber moulding and conventional pattern manufacturing by metal mould are also presented.
Nowadays world is exposing a continuous spreading of composites applications and, as a consequence an enforcement of scientist efforts toward such materials design, testing and modelling. Since polymer reinforced materials are covering a huge area of applications it is obvious that the researchers interest is oriented to these materials study in all its aspects. Fabric reinforced polymers represent a very attractive solution from the manufacturers’ point of view, especially in the case of thermoset polymers where the lay-up method is the most used to form composites. This study is about tensile behavior of lamina or plies of thermoset matrix fabric reinforced materials. The aim of the study is to determine the role of the matrix and the role of fabric (fibers type, specific weight) on the tensile response to gather valuable information regarding the design of layered materials.
The purpose of this article is to present an overview of the trend of using, on a wider scale, plastics in the automotive industry. It is presented the realization of PLA-TPU-Blends with a biogenic mass greater than 90%, by mixing thermoplastic Polyurethan (TPU) with Polylactid-Acid (PLA) at IKT University of Stuttgart. In order to estimate the possibilities of use of bio-materials made from PLA and TPU, the properties were compared with standard thermoplastics such as Polypropylen (PP), Polyethylen (PE), Polyamid (PA), as well as with better performing materials from the engineering thermoplastics range. PBT, ASA and their derivatives. Notable are the properties of PLA-TPU-Blends compared with standard thermoplastics PP, PE, PA. The results show PLA-TPU-Blends superiority in Yeld strength compared to the types of Polypropylene homopolymer (PP-H), block-copolymer (PP-B) and randompolymer (PP-R), the properties being adaptable by flexible modification of the ratio between the components, according to the requirements of the application. Using suitable additives to make components compatible, there were created blends which were partially cross-linked, but their properties remain of thermoplast. When reinforcing PLA-TPU-Blends with fibers (glass and natural), the components also react with the groups (-OH) on the fiber surface, thus making a good connection between fibers and blends, which prevents the so-called pull-out-effect. PLA-TPU-Blends reinforced with natural fibers can be used to make the interior body elements of vehicles. The paper also presents a comparison between bio-materials made at IKT University of Stuttgart with Polyethylen (PE) and other industry standard bio-materials.