Johnson-Cook (JC) constitutive equation for ZGMn18 high manganese steel

In the Finite element simulation, the constitutive equation of the material has an important influence on the simulation results. In order to obtain the constitutive model of ZGMn18 high manganese steel, the constitutive model of ZGMn18 high manganese steel under the condition of quasi-static strain rate at room temperature (10-1s-1, 10-2s-1, 10-3s-1) compression experiment was conducted to obtain the compression experimental data of ZGMn18 high manganese steel at different rates. According to the experimental results, the parameters of Johnson-Cook constitutive equation of ZGMn18 high manganese steel are deduced, and the Johnson-Cook constitutive model of ZGMn18 high manganese steel at room temperature is obtained. Finally, the prediction results of the model are compared with the experimental data, and the prediction curves are in good agreement, which verifies the feasibility of the model

Feasibility analysis of short process flexible precision forming of aluminum alloy automobile hollow shaft

Aiming at the large weight of automobile steel solid shaft, this paper innovates aluminum alloy hollow shaft. The rolling process of automobile hollow shaft was simulated by using the short process flexible precision forming process and the Finite Element Method (FEM). The variation of the shape and inner hole of the rolled piece, the roundness of the outer surface and the wall thickness during the rolling process were analyzed. The numerical results verify the feasibility of rolling aluminum alloy automobile hollow shaft by this process, and provide a theoretical basis for forming aluminum alloy automobile hollow shaft in China

Research on force control system of lead cathode leveler

The flatness of the lead cathode plate affects the electrolytic efficiency of lead and the production efficiency of the whole lead electrolytic industry. However, the dynamic response of the force control system of the leveler is slow, and the anti-interference and robustness are poor. By comparing proportion integration differentiation (PID) control and feedback linearized synovial control two control strategies, MATLAB software was used for modeling and simulation analysis. The results show that the system with feedback linearized sliding mode control has faster response, higher precision and better robustness

Classification and Segmentation of MRI Images of Brain Tumors Using Deep Learning and Hybrid Approach

Manual prediction of brain tumors is a time-consuming and subjective task, reliant on radiologists\u27 expertise, leading to potential inaccuracies. In response, this study proposes an automated solution utilizing a Convolutional Neural Network (CNN) for brain tumor classification, achieving an impressive accuracy of 98.89%. Following classification, a hybrid approach, integrating graph-based and threshold segmentation techniques, accurately locates the tumor region in magnetic resonance (MR) brain images across sagittal, coronal, and axial views. Comparative analysis with existing research papers validates the effectiveness of the proposed method, and similarity coefficients, including a Bfscore of 1 and a Jaccard similarity of 93.86%, attest to the high concordance between segmented images and ground truth

Prehrambene navike i tjelesna aktivnost

Tjelesna aktivnost i pravilna prehrana važni su za očuvanje zdravlja tijela sada i u budućnosti. Pravilna prehrana i tjelesna aktivnost smanjuju rizik od razvoja mnogih bolesti. Uslijed razvoja tehnologije djeca sve manje vremena provode izvan kuće na igralištu, a sve više vremena provode uz televiziju, računala, pametne telefone, PlayStation. Roditelji također zbog ubrzanog načina života imaju manje vremena za kuhanje. U ovom radu istražili smo kakva je situacija s obzirom na tjelesnu masu učenika 7. razreda OŠ Izidora Poljaka Višnjica, a nakon toga smo proveli istraživanje s učenicima i roditeljima u kojem smo ispitali njihovo znanje o hrani, hranjivim tvarima i kalorijskoj vrijednosti namirnica te njihove prehrambene navike i navike vezane uz bavljenje tjelesnom aktivnošću. Najviše učenika 7. razreda naše škole ima poželjnu tjelesnu masu, ali prehrambene navike učenika i roditelja nisu u skladu s pravilnom prehranom. Učenici i roditelji nemaju dovoljno znanja o namirnicama, hranjivim tvarima koje se nalaze u njima i u kojoj količini. Također nemaju dovoljno znanja o kalorijskoj vrijednosti namirnica. Roditelji učenika su dobro informirani o zdravom načinu života ali to ne primjenjuju

Chemical composition and potential antioxidant, anti-inflammatory, and analgesic efficacy of Cistus albidus L.

This study aims to assess the chemical composition of the aqueous extract of Cistus albidus L. leaves, as well as the potential of aqueous and hydroethanol extracts of the leaves and seeds as analgesic, anti-inflammatory, and antioxidant agents. The contents of phenolics and inorganic constituents were determined in C. albidus seeds and leaves; antioxidant capacity was assessed by 3 complementary and diverse tests. The carrageenan-induced paw edema technique was used to investigate the anti-inflammatory effect in vivo, and albumin denaturation to evaluate the anti-inflammatory effect in vitro. The acetic acid-induced contortion test, the tail-flick test, and the plantar test were used to assess the analgesic efficacy in vivo. Chemical analysis was performed by UPLC-MS/MS to quantify several phenolic compounds including catechin (1,627.6 mg kg–1), quercitrin (1,235.8 mg kg–1) and gallic acid (628. 2 mg kg–1). The ICP analysis revealed that potassium and calcium were the main inorganic components in the seeds and leaves of C. albidus. The hydroethanolic extract of the leaves showed the highest content of polyphenols/flavonoids, whereas the highest value of proanthocyanidins was detected in the aqueous extract of the seeds. All extracts showed potent antioxidant activity related to different phenolic compounds (quercetin, gallic acid, astragalin, catechin, and rutin). The aqueous extract of the leaves strongly inhibited paw edema (76.1 %) after 6 h of treatment and showed maximal inhibition of protein denaturation (191.0 µg mL–1 for 50 % inhibition) and analgesic activity in different nociceptive models. The presented data reveal that C. albidus extracts potentially show antioxidant, anti-inflammatory, and analgesic activities that could confirm the traditional use of this plant

Optimization Analysis of the Structural Design and Stability Parameters of a Rehabilitation Robot

In this paper, a lower limb rehabilitation robot, suitable for stroke patients, is designed to meet the needs of the lower limb training in a later stage of rehabilitation. The rehabilitation robot is composed of a gantry structure, a driving system, a weight support system, and a human-computer interaction system. Such a robot can assist the patients to stand and walk on the ground. Because of the weakness of the lower limbs on the affected side, stroke patients find it difficult to maintain their own body balance. The patients may fall due to a change in body posture caused by insufficient body function. Therefore, it is necessary to evaluate the stability of the rehabilitation robot after being impacted by the patient\u27s fall during use. This paper presents a method for the analysis of robot stability and develops an approximate mathematical model of the rehabilitation robot stability based on the response surface method. Optimal structural design parameters for the rehabilitation robot under impact are determined based on the response surface mathematical model. Finally, a stability experiment of the rehabilitation robot under the optimal structural parameters is performed. The experimental results demonstrate that the universal wheel maintains a close force contact with the ground, which proves the reliable stability of the robot

Evaluation of strength parameters and structure analysis of an EN AW - 7075 aluminium alloy ring made by forging and rolling and heat-treated

The article presents the results of research on the evaluation of the structure and mechanical properties of a largesize ring made of aluminum alloy EN AW - 7075 according to a new technology, developed under the project “Innovative low-waste technology for forming large-size rings” carried out by Zarmen FPA forge with participation and support of the Lukasiewicz Research Network - Poznan Institute of Technology. Based on the tests, it was found that the produced ring was characterized by a homogeneous structure and the strength properties required by the customers

Research on the cyclic load life of automobile bellows

In this study, a Finite Element Computational (FEC) model for automotive bellows exhaust pipes is established, and the impact of displacement loads on their fatigue life is investigated. The relationships between various structural parameters of the exhaust pipes and stress, strain, and cycle counts are elucidated. Furthermore, the bellows’ structure is optimized through an orthogonal experiment. A microscopic morphological analysis is conducted on 309S stainless steel automotive bellows exhaust pipes after fatigue failure. The findings indicate that as displacement loads increase, the fatigue life of the bellows exhaust pipes decreases. The error between finite element analysis and experimental results is found to be less than 8,8 %. During the water swell forming stage, partial martensite is produced due to cold deformation. Under alternating loads, with noticeable cracks at the wave peaks, indicating the presence of internal fatigue characteristics

Exploring the Landscape of Research on Enterprise Green Environments Through Science Mapping Analysis

This study employs science mapping and bibliometric analysis to chart the knowledge structure and research trajectory of enterprise green environment literature from 2002 to 2022. Despite rising interest, comprehensive analyses of this field\u27s research landscapes and dynamics remain scarce. Through advanced techniques including discipline mapping, journal co-citation analysis, author co-citation analysis, and keyword co-occurrence analysis, this work elucidates the prominent disciplines, publications, authors, and research foci in enterprise of green environment scholarship over the past two decades. The results provide vital insights into the current status, influential leaders, core journals, knowledge gaps, and future directions of this rapidly evolving field. This science mapping analysis offers a valuable quantitative overview of green environment research enterprise that can inform scholars worldwide in producing impactful work on this critical area. The findings reveal profound implications for the developing structure and frontiers of sustainability-focused business and management research