APLICAÇÃO DA TÉCNICA DE KAIZEN EM UMA INDUSTRIA DE MATERIAIS PLASTICOS

In this article we will discuss and talk about how the Kaizen technique came about, how it was updated over time, as well as exemplifying how this technique came to transform and reform the industrial production line. From it, it was possible to help the search for better results in the companies, since its implementation is totally correlated to the focus on cost reduction and the good performance of the production line and, consequently, in obtaining effective profitability of the company. Posteriorly, we will exemplify how the technique is used in a company that operates in the plastic transformation and production segment.

Stress Relief and Support for Stability of Deep Mining Roadway with Thick Top Coal in Hujiahe Coal Mine with the Risk of Rock Burst

Rock burst is a typical dynamic disaster in deep underground coal mining. Based on the support problems of the deep roadways in fully mechanized caving face 401111 of Hujiahe Coal Mine suffering from rock burst in Shaanxi Province of China, the failure law and influencing factors of the surrounding rock of the roadway are analyzed. The results show that the deformation of surrounding rock in the roadway shows the characteristics of elastic, plastic transformation, rheology, and expansion. At the same time, it has the typical characteristics of deep roadway, such as the fast deformation speed, long duration, asymmetric deformation, and large loose broken area of surrounding rock. Based on the principle of “strengthening support in shallow zones” and “deep pressure relief in deep zones” in the surrounding rock, the control scheme of surrounding rock in the return roadway of fully mechanized caving working face 401111 is proposed by taking the large diameter pressure relief and deep hole blasting as the main means of pressure relief. The practice shows that the surrounding rock of the return roadway is relatively stable after the implementation of the new scheme, which shows that the design of the new support scheme is reasonable and reliable. It is of great significance for the stability control of surrounding rock of the mining roadway suffering from rock burst.

Control algorithm for an elastic-viscoplastic model to study processes of shock interaction of bodies

Introduction. In engineering practice, dynamic processes, with the help of which mechanics of interaction of machine components and structural elements are described and studied, are of great importance. These dynamic processes are the cause of large deformations leading to the destruction. The research objective is to develop a more accurate shock simulation algorithm through the controlled transformation of the mechanorheological shock process model from elasticviscous to elastic-viscoplastic.Materials and Methods. Differential equations of the model movement are proposed. The conditions for the transformation of the model during the transition from elastic to plastic deformations, from the stage of loading the model to the stage of unloading under the shock interaction with the surface, are considered. When calculating deformations, the assumption is made that elastic and plastic deformations occur simultaneously from the very onset of the impact. The model functioning method is considered in detail, the algorithm of the model operation is developed, the logic of its functioning is described in detail.Results. To study shock processes, a mechanoreological elastic-viscoplastic model was developed. An important parameter of the model is the force corresponding to the onset of plastic deformation. As a result of the research, a more perfect algorithm was created, and a new computer program was developed to study the shock process using an elasticviscoplastic model with an adjustable elastic-plastic transformation. Discussion and Conclusions. The results obtained can be used to improve the accuracy and reliability of simulation of shock processes in order to further develop the techniques for determining the physical and mechanical characteristics of materials by shock methods. Knowledge of the mechanical characteristics of materials is required when solving various research problems through mathematical modeling of vibration and shock processes. At the same time, an important task is to adapt the design model to the real shock process, for which it is required to develop appropriate methods and techniques.

Reliability analysis of a plastic processing equipment: a case study supported by statistical software

The extrusion process of plastic transformation involves a series of variables and components which must be associated with the concept of reliability to achieve an expected performance in operational and quality terms. This paper describes the reliability framework of an extruder of a packaging company located in Brazil through the following mathematical representations: probability density function f(t), reliability curve R(t) and function rate of failure h(t). Through a statistical software and under the light of classical concepts of reliability analysis, the set of representations evidenced high probability of fault occurrence at the beginning of operating time, which was shown by the density function and the accumulated failure charts. Besides that, in the current operating conditions of the machine, approximately 50% of the failure observations happen on the hour 106 of operating time. It is expected that this work may act as a guide for future implementation of improvement activities.

Recruitment and Expansion of Tregs Cells in the Tumor Environment—How to Target Them?

Regulatory T cells (Tregs) are present in a large majority of solid tumors and are mainly associated with a poor prognosis, as their major function is to inhibit the antitumor immune response contributing to immunosuppression. In this review, we will investigate the mechanisms involved in the recruitment, amplification and stability of Tregs in the tumor microenvironment (TME). We will also review the strategies currently developed to inhibit Tregs’ deleterious impact in the TME by either inhibiting their recruitment, blocking their expansion, favoring their plastic transformation into other CD4+ T-cell subsets, blocking their suppressive function or depleting them specifically in the TME to avoid severe deleterious effects associated with Treg neutralization/depletion in the periphery and normal tissues.

A comparison of different hardening rules on a multi-step global manufacturing process modeling

The main difficulty presented by the simulation of a global process that includes different forming stages is the correct characterization of the material state at the end of each of these stages, which in turn, are the initial point of the following process. Hardening variables are capable of characterizing the state of the material, which, after a plastic transformation, varies according to the direction of the solicitation and its intensity. The present work carries out an analysis of the influence in the election of the hardening rule used in the behavior law, comparing the most used approach. For a work piece solicited by combined efforts in multiple stages, results are obtained by numerical simulation. A correct choice will allow obtaining reliable predictions, not the solicitations but also to the final geometry and the dissipated energy in the global process, allowing an eventual optimization of such process.

Elastic-Plastic Threshold and Rational Unloading Level of Rocks

During loading and unloading test, various rocks manifest different stress values of elastic-plastic transformation. This study proposes to include axial pressure increment ratio in the conventional triaxial compression test to evaluate different variables (nominal elastic modulus, nominal Poisson’s ratio, strain, and energy). The relationships among various factors including variables, the stress level of initial confining stress and axial pressures, were analyzed by analyzing the stress–strain plot record obtained from testing various rocks. The extreme value point of the deformation parameter, also known as the elastic-plastic threshold, was analyzed. In addition, the elastic-plastic thresholds were later used as unloading points during the unloading tests. Under the same confining condition, different rocks demonstrated different unloading levels. Furthermore, a linear correlation was observed between unloading levels and changing confining pressures, and the gradient is mainly related to the types of rocks. During the unloading tests of rocks, the rational unloading level is recommended to be no higher than the stress level at the elastic-plastic threshold under the corresponding confining pressure.

P14.101 Glioblastoma survival outcomes related to cortical/neural stem cells regions

BACKGROUND Subventricular brain zone (SVZ) and hippocampal regions are supposed to harbor astrocyte-like neural stem cells. While some tumors may arise from transformed SVZ stem cells, other may be initiated by neo-plastic transformation of non-SVZ progenitor cells or mature glial cells. Lim′s et al classification (Neuro-Oncology 2007) of initial glioblastoma location, related to these neural stem cells regions, was predictive for invasive and multifocal tumor phenotype. The aim of this retrospective single-institutional study is to evaluate the relations of this Lim classification on survival parameters in unselected cohort of glioblastoma patients. MATERIAL AND METHODS Patients treated between 2014–2017 were grouped according to initial location of their contrast enhancing lesion as follows: Lim1 (SVZ+⋯SVZ/hippocampal involvement and Cortex+⋯cortex involvement), Lim2 (SVZ+ and Cortex-), Lim3 (SVZ- and Cortex+) and Lim4 (SVZ- and Cortex-). All patients underwent radiotherapy, some patients were indicated to full treatment according to Stupp regimen (at least 3 cycles of adjuvant chemotherapy after postsurgery chemoradiotherapy). RESULTS In total, 144 patients were analyzed (94 men, mean age 59 years). 47 patients (30.5%) were treated according to Stupp regimen. Lim1 classification was presented in 74 (48%) patients, Lim2 in 22 (14.3%), Lim3 in 50 (32.5%) and Lim4 in 8 (5.2%) patients. Cortical structures (Lim1 and Lim3) were involved in 124 (80.5%) patients. Median overall survival was significantly better in patients treated according to Stupp regimen (23.3 vs. 8.6 months, p<0.001). Median overall survival differs in respective Lim groups: 12.3, 5.6, 11.8 and 6.6 months (p=0.07). Better survival was in patients with cortical involvement (Lim1+Lim3): 12.3 vs. 6.4 months (p=0.02), especially in subgroup of patients who were not treated according to Stupp regimen (8.9 vs. 4.4 months, p=0.02) vs. those after Stupp regimen (23 vs. 23.4 months, p=0.7). CONCLUSION Initial location of enhancing glioblastoma was prognostic for overall survival, with better outcomes in patients presented by involvement of cortical structures comparing to subventricular/hippocampal zones. Molecular patterns may further clarify potential effects of neural stem cells in glioma genesis mirrored in different clinical behavior and location of initial tumor. Supported by Ministry of Health of the Czech Republic, grant No. 18-03-00469