Study on multi-objective optimization of X12M steel milling process by reference ideal method

For all machining cutting methods, surface roughness is a parameter that greatly affects the working ability and life of machine elements. Cutting force is a parameter that not only affects the quality of the machining surface but also affects the durability of cutter and the level of energy consumed during machining. Besides, material removal rate (MRR) is a parameter that reflects machining productivity. Workpiece surface machining with small surface roughness, small cutting force and large MRR is desirable of most machining methods. Milling is a popular machining method in the machine building industry. This is considered to be one of the most productive machining methods, capable of machining many different types of surfaces. With the development of the cutting tool and machine tool manufacturing industries, this method is increasingly guaranteed with high precision, sometimes used as the final finishing method. Milling using a face milling cutter is more productive than using a cylindrical cutter because there are multiple cutter s involved at the same time. This article presents a study of multi-objective optimization of milling process using a face milling cutter. The experimental material used in this study is X12M steel. Taguchi method has been applied to design an orthogonal experimental matrix with 27 experiments (L27). In which, five parameters have been selected as the input parameters of the experimental process including insert material, tool nose radius, cutting speed, feed rate and cutting depth. The Reference Ideal Method (RIM) is applied to determine the value of input parameters to ensure minimum surface roughness, minimum cutting force and maximum MRR. Influence of the input parameters on output parameters is also discussed in this stud

Prognostic Models in Dengue

Reliable prediction models in dengue would facilitate early identification of patients likely to progress to more severe disease, potentially improving patient management. However, most published studies have limitations with respect to their modelling strategy, sample size, and Chosen clinical outcomes, and to date none have exploited longitudinal data. Moreover, only a few studies have examined outcomes in patients presenting with dengue shock syndrome (DSS), the most severe form of the disease. This thesis aims to overcome these limitations by using two large prospective datasets describing a) 1719 children with established DSS and b) 2598 children hospitalized with dengue. First, the population of children with DSS was characterized, and profound DSS, a composite outcome reflecting the need for intensive supportive care, was established as a suitable outcome for prognostic research in this population. Second, risk factors for profound DSS were identified and included in a robust prediction model. Based on this model, a simple score chart for use in clinical practice was derived. Third, risk factors for progression to DSS among children hospitalized with dengue were identified, and a prognostic model for progression to DSS was carefully developed. However, this model displayed only moderate performance and had limited clinical utility. Lastly, differences between acute and chronic diseases, and the implications for dynamic prediction modeling based on longitudinal data, are discussed. A case study of dynamic prediction modeling for development of DSS suggested that (1) the current platelet count can be used to improve baseline models that rely on enrolment values only, and (2) simple conditional dynamic models displayed similar performance to more complex joint models in this situation

On Business Services Representation – The 3 x 3 x 3 Approach

The increasing popularity and influence of service-oriented computing give rise to the need of representational and methodological supports for the development and management of business services. From an IT perspective, there is a proliferation of methods and languages for representing Web services. Unfortunately, there has not been much work in modeling high-level services from a business perspective. Modeling business services should arguably capture their inherent features, along with many other representational artifacts. We propose a novel approach for business services representation featuring a three-dimensional representational space of which dimensions stand for the service consumer, service provider and service context. We also discuss how the proposed representation approach provides methodological supports to the area of service orientation. Finally, we present in-progress work on the application of our approach

Polar active liquids: a universal classification rooted in nonconservation of momentum

We study the spatially homogeneous phases of polar active particles in the low density limit, and specifically the transition from the isotropic phase to collective polar motion. We show that the fundamental quantity of interest for the stability of the isotropic phase is the forward component of the momentum change induced by binary scattering events. Building on the Boltzmann formalism, we introduce an ansatz for the one-particle distribution and derive a closed-form evolution equation for the order parameter. This approach yields a very intuitive and physically meaningful criterion for the destabilization of the isotropic phase, where the ansatz is exact. The criterion also predicts whether the transition is continuous or discontinuous, as illustrated in three different classes of models. The theoretical predictions are in excellent agreement with numerical results.Comment: 20 pages, 6 figures Publised at IOP, Journal of Statistical Mechanics, available at http://dx.doi.org/10.1088/1742-5468/2015/10/P1001

Key Factors Influencing Customer Satisfaction and Intention to Reuse Food Ordering Apps

This empirical study aims to identify and evaluate the crucial factors that influence customer satisfaction and their intention to reuse a food ordering app (FOA) in Ho Chi Minh City (HCMC), Vietnam. A data sample of 413 observations from customers who used the FOA was used to test hypotheses using a quantitative technique and a structural linear model. The results indicated that among the four key factors, performance expectancy, price value, and online reviews had direct and indirect effects on customers’ continued intention to use the FOA. By contrast, hedonic motivation only had an indirect effect. Satisfaction level was the mediating factor that affected customers’ continuance intention. This study provided insights into the online service and how the key factors affected customers’ satisfaction level towards the intention to reuse the FOA. When the management of the online providing service improves the key factors – performance expectancy, hedonic motivation, price value, and online reviews – they will improve the level of satisfaction towards the intention to reuse the FOA of customers in HCMC. The management of food companies should refer to this research model for restructuring and improving their business to satisfy the needs and wants of their target customers in the competitive market

Research on calculation of grinding surface roughness

In machining processes, grinding is often chosen as the final machining method. Grinding is often chosen as the final machining method. This process has many advantages such as high precision and low surface roughness. It depends on many parameters including grinding parameters, dressing parameters and lubrication conditions. In grinding, the surface roughness of a workpiece has a significant influence on quality of the part. This paper presents a study of the grinding surface roughness predictions of workpieces. Based on the previous studies, the study built a relationship between the abrasive grain tip radius and the Standard marking systems of the grinding wheel for conventional and superabrasive grinding wheels (diamond and CBN abrasive). Based on this, the grinding surface roughness was predicted. The proposed model was verified by comparing the predicted and experimental results. Appling the research results, the surface roughness when grinding three types of steel D3, A295M and SAE 420 with Al2O3 and CBN grinding wheels were predicted. The predicted surface roughness values were close to the experimental values, the average deviation between predictive results and experimental results is 15.11 % for the use of Al2O3 grinding wheels and 24.29 % for the case of using CBN grinding wheels. The results of the comparison between the predicted model and the experiment show that the method of surface roughness presented in this study can be used to predict surface roughness in each specific case. The proposed model was verified by comparing the predicted and measured results of surface hardness. This model can be used to predict the surface hardness when surface grindin

CONCEPTS AND AWARENESS ABOUT SELF-HARM AND SUICIDAL THOUGHTS AMONG HIGH SCHOOL STUDENTS CURRENTLY

The article focuses on understanding concepts and awareness of suicidal thoughts and self – harm behaviors based on quantitative and qualitative data. The quantitative database will be taken from a survey of high school students living and studying in Ho Chi Minh City. The qualitative database is taken from in-depth interviews focusing on teachers, parents, and students. The article presents the main results of the research. First, focus on the research basis including subjects, objects, and research methodology. Second, include views on suicidal thoughts and self-harm from many different perspectives, manifestations and causes of these behaviors, the prevalence of self-harm/suicidal thoughts, and consequences. Third, conclude and propose some recommendations to minimize the problem

Changes in physiological and biochemical parameters during the growth and development of guava fruit (Psidium guajava) grown in Vietnam

This research examined the ripening time of guava fruit to provide a scientific basis for better harvesting and preservation of these fruits. Biochemical research methods were used to analyse changes in physiological and biochemical parameters according to the growth and development of guava fruit. The fruit took 14 weeks after anthesis to reach its maximum size in terms of length and diameter. The chlorophyll content in guava peel peaked after 10 weeks, decreasing until week 15. The content of carotenoids, which was low at fruit formation, rose rapidly until fruit ripening, while the vitamin C and reducing sugar contents increased continuously and peaked at week 14. A gradual increase was seen in the starch and total organic acid contents from the beginning of fruit formation, with peaks at 10 weeks, followed by a moderate downward trend. The pectin content showed the same trend, as it declined gradually after peaking at 12 weeks. The first 4 weeks showed an increase in the tannin content, which decreased afterward. The study results show that guava fruit should be harvested after physiological maturity and before ripening completely (14 weeks) to ensure that the nutritional value of the fruit is maintained during storage. Highlights• Xa Li guava at 14 week after anthesis to reach its maximum size in terms of length and diameter. • The chlorophyll content in guava peel peaked after 10 weeks, decreasing until week 15. The content of carotenoids, which was low at fruit formation, rose rapidly until fruit ripening.• The vitamin C and reducing sugar contents peaked at week 14. A gradual increase was seen in the starch and total organic acid contents and peaks at 10 weeks, followed by a moderate downward trend. • The pectin content showed the same trend, as it declined gradually after peaking at 12 weeks. The first 4 weeks showed an increase in the tannin content, which decreased afterward.This research examined the ripening time of guava fruit to provide a scientific basis for better harvesting and preservation of these fruits. Biochemical research methods were used to analyse changes in physiological and biochemical parameters according to the growth and development of guava fruit. The fruit took 14 weeks after anthesis to reach its maximum size in terms of length and diameter. The chlorophyll content in guava peel peaked after 10 weeks, decreasing until week 15. The content of carotenoids, which was low at fruit formation, rose rapidly until fruit ripening, while the vitamin C and reducing sugar contents increased continuously and peaked at week 14. A gradual increase was seen in the starch and total organic acid contents from the beginning of fruit formation, with peaks at 10 weeks, followed by a moderate downward trend. The pectin content showed the same trend, as it declined gradually after peaking at 12 weeks. The first 4 weeks showed an increase in the tannin content, which decreased afterward. The study results show that guava fruit should be harvested after physiological maturity and before ripening completely (14 weeks) to ensure that the nutritional value of the fruit is maintained during storage. Highlights• Xa Li guava at 14 week after anthesis to reach its maximum size in terms of length and diameter. • The chlorophyll content in guava peel peaked after 10 weeks, decreasing until week 15. The content of carotenoids, which was low at fruit formation, rose rapidly until fruit ripening.• The vitamin C and reducing sugar contents peaked at week 14. A gradual increase was seen in the starch and total organic acid contents and peaks at 10 weeks, followed by a moderate downward trend. • The pectin content showed the same trend, as it declined gradually after peaking at 12 weeks. The first 4 weeks showed an increase in the tannin content, which decreased afterward