Working Behavior Research Articles

Impact of residual stresses on mechanical behaviour of hot work steels

Abstract This paper presents a multi-scale analysis of the mechanical behaviour of hot work steels taking into account the effect of residual stress generated by the initial microstructure and the external load and induced industrially by heat treatment and machining process. The methodology is based on: i) laboratory study to evaluate the macroscopic behaviour of the material, ii) numerical simulation based on finite element and homogenisation approaches to evaluate the material's microstructure complexity and characterize the residual stress distribution, iii) industrial tests during pretreatment and forging process of valve gas parts in order to complete the results obtained at laboratory scale. It was proved that residual stress induced by the initial microstructure of the hot steel material has significant effects on the stress behaviour of the hot forging steel under static tensile load. Besides, the residual stress generated during the manufacturing process affected more significantly the stress distribution on the die surface than the heat treatment, inducing residual stress close to plastic deformation.

Isothermal forging of titanium aluminides without beta-phase — Using non-equilibrium phases produced by spark plasma sintering for improved hot working behavior

This paper investigates the hot forgeability of a TNB-V5 (Ti–45Al–5Nb–0.2B–0.2C, at.%) alloy produced by spark plasma sintering (SPS) from pre-alloyed powder particles using the concept of processing maps. For the first time in this paper, to the best of our knowledge, we report the possibility of the isothermal forging of a TiAl alloy without the necessity to induce the ductile β-phase in the microstructure, by using non-equilibrium phases produced by SPS. At room temperature, the SPSed sample reveals a homogeneous equiaxed microstructure consisting of globular α2-and γ-grains with the α2-phase formed mainly at the necks between powder particles as confirmed by EBSD analyses. The necks contain a lower Al content and thus transform into α-phase upon heating to forging temperature. A stable plastic flow is observed for all ranges of the studied strain rates. The presence of a fine equiaxed microstructure at hot working temperature seems to ensure good workability and leads to a relatively wide processing window. The processing map reveals two safe processing windows for the studied alloy. The lower strain rate domain (10−3-10−2 s−1) corresponding to a strain rate sensitivity value of ≈0.8 represents superplasticity of the fine and uniform (α+γ) equiaxed microstructure. The higher strain rate domain (10−2-10−1 s−1, T > 1215 °C) with a strain rate sensitivity value of ≈0.45 represents dynamic recrystallization of the α-grains at elevated temperatures. The processing map also exhibits a domain of flow instability represented by the deformation conditions of T < 1215 °C and ε˙ > 10−2 s−1, which might result from the void formation and/or cracking. Although the TNB-V5 alloy was not designed for forging operations, the SPS process can create a homogeneous equiaxed microstructure consisting of globular α- and γ-grains decorating the interfaces and triple junctions between former powder particles leading to a good hot workability. The current study offers a new process design strategy by opening up the possibility of using local non-equilibrium conditions in the material during the forging process, which could stabilize the ductile phases locally.

Reducing Free Riding Behaviour in Collaborative Work with Computer Supported Tools

Free riding behaviour is a problem that has been around for many years. With all the new technological advances, there is much more collaborative work supported by online tools. These developments make it easier for individuals to become a free rider. This research carried out a literature study, to find the best method to reduce free-riding behaviour. Besides the methods, this study also elaborates some factors that trigger free riders in a group. The methods which are highlighted in this research are the implementation of assessments, group awareness tools, sufficient group size and enhancing team morale. However, the study found that none of the methods cover all the aspects of free-riding behaviour. It is suggested by this research to combine and improve various methods, to a new method that can effectively reduce free-riding behaviour in collaborative work with computer-supported tools.

Connected Process Design for Hot Working of a Creep-Resistant Mg–4Al–2Ba–2Ca Alloy (ABaX422)

With a view to design connected processing steps for the manufacturing of components, the hot working behavior of the ABaX422 alloy has been characterized for the as-cast and extruded conditions. In the as-cast condition, the alloy has a limited workability, due to the presence of a large volume of intermetallic phases at the grain boundaries, and is not suitable to process at high speeds. A connected processing step has been designed on the basis of the results of the processing map for the as-cast alloy, and this step involves the extrusion of the cast billet to obtain a 12 mm diameter rod product at a billet temperature of 390 °C and at a ram speed of 1 mm s−1. The microstructure of the extruded rod has a finer grain size, with redistributed fine particles of the intermetallic phases. The processing map of the extruded rod exhibited two new domains, and the one in the temperature range 360–420 °C and strain rate range 0.2–10 s−1 is useful for manufacturing at high speeds, while the lower temperature develops a finer grain size in the product to improve the room temperature strength and ductility. The area of the flow instability is also reduced by the extrusion step, widening the workability window.

Enhancement of Strength and Hot Workability of AZX312 Magnesium Alloy by Disintegrated Melt Deposition (DMD) Processing in Contrast to Permanent Mold Casting

AZX312 (AZ31-2Ca) magnesium alloy, with starting conditions of as-cast (AC), cast-homogenized (CH), and disintegrated melt deposition (DMD), is examined in terms of its compressive strength and hot working behavior to establish the relative merits and limitations of these processing routes. Processing maps are developed in the temperature range of 300–500 °C and strain rate range of 0.0003–10 s−1, and mechanisms of hot deformation are established based on microstructures, tensile ductility, and activation parameters. The alloy in AC and CH conditions has a large grain size with intermetallic phases at the grain boundaries and in the matrix. In DMD processed alloy, the grain size is very small and the phases are refined and distributed uniformly. The compressive strength is significantly improved by DMD processing, which is attributed to the grain refinement. The processing maps for AC and CH conditions are similar, exhibiting only a single workability domain, while the DMD processed alloy exhibited three domains that enhanced workability. The additional workability domain at higher strain rates is an advantage in designing forming processes that facilitates faster production, while the fine grain size produced by a finishing operation in the lower temperature domain will improve the mechanical properties of the product.

Achieving sustainable behavioral changes of daily work practices

PurposeProcess-oriented behavior is a prerequisite for transforming a company into a process-oriented organization, but is difficult to achieve among employees. The purpose of this paper is to examine the effectiveness of role plays on adapting process-oriented behavior in daily work practices.Design/methodology/approachUsing the theory of cognitive dissonance, the authors investigate whether role plays are an effective learning method. This study was conducted over a period of two years and included 212 participants of a financial services provider.FindingsThe results reveal that the role play used had a persistent impact on employees’ process-oriented behavior in terms of their process knowledge, their cross-functional coordination, and their continuous process reflection, but not on their process awareness. Thus, the authors conclude that despite high application costs, role plays are beneficial for financial services companies to train their employees.Research limitations/implicationsWhile the data stem from participants within one financial service provider only, this study contributes to the understanding how process-oriented behavior can be promoted sustainably in organizations.Practical implicationsThe results indicate that companies aiming for process orientation should apply role plays to achieve a change in behavior of employees.Originality/valueThis research contributes to the understanding of role plays as an effective learning method to adopt process-oriented behavior.

Las Competencias Profesionales del Docente: Su Incidencia en el Proceso de Titulación en el Instituto Superior Tecnológico de Formación Profesional Administrativa Y Comercial De Ecuador

La calidad del trabajo docente, científico e investigativo es reconocida cada vez más como rasgo distintivo del desarrollo de la comunidad docente en la educación superior y está considerado como factor clave para incrementar la competitividad y excelencia de este nivel educativo. Por tanto, el desafío que se les presenta a la universidad del siglo XXI, en particular el Instituto Superior Tecnológico de Formación Profesional Administrativa y Comercial (ITFPAC) en Ecuador es elevado, si se tiene en cuenta que debe enfrentar las nuevas exigencias sociales, profesionales y científicas de la postmodernidad. Un índice de calidad que da cuenta de lo expresado es el rendimiento académico y la eficiencia terminal. En tal sentido, el trabajo de titulación que realiza el Instituto Superior Tecnológico de Formación Profesional Administrativa y Comercial (ITFPAC) es vital para dar respuesta a esta exigencia. En correspondencia con lo expuesto se realizó un análisis de los últimos tres años para valorar el comportamiento del trabajo de titulación que realizan los estudiantes, revelando que las competencias profesionales de los docentes incidieron directamente en la elevación de la eficiencia terminal de la institución, lo cual contribuyó al éxito del proceso de evaluación y acreditación.

A study to assess the effectiveness of information, education, and communication package on management of mentally challenged children among mothers of the children in The Spastic Society of TamilNadu, Chennai.

The aim of the study is to assess the effectiveness of information, education and communication package on management of mentally challenged children. Mentally challenged is a disability that occurs before the age of 18 years. It is considered by significant restrictions in intellectual working and adaptive behavior as stated in theoretical, social and practical adaptive skills. The mothers are the ones who provide the environment to mentally challenged children for better progress. While taking care of the mentally challenged children, the mother should know about the condition of the child to develop the skills of their children. The study adopted a pre experimental one group pre test post test design to assess the effectiveness of information, education, and communication package on management of mentally challenged children among mothers of the children in The Spastic Society of TamilNadu, Chennai. The sample size was 50 mothers of mentally challenged children aged 1 – 12 years. Convenient sampling technique was used. The tool has three parts. Part I consists of demographic variables of mother, part II consists of self administered questionnaire regarding management of mentally challenged children and part III consists of information, education and communication package on management of mentally challenged children. Analysis was done by using the descriptive and inferential statistics. The results indicated that, there is a significant difference in the pre test and post test score of mothers after attending the information, education and communication programme. There was a increase in the mean value from 13.76 to 24.76 before and after giving an information, education and communication package. The calculated‘t’ test was 17.28, which was found to be highly significant at p>0.05 level, indicating an increase in the level of knowledge following teaching program. Analysis revealed that there was a significant association between education level of the mother, family income and level of knowledge.

A Novel Approach for Brushless DC Motors Characterization in Drones Based on Chaos

A novel technique named Signal Analysis based on Chaos using Density of Maxima (SAC-DM) is presented to analyze Brushless Direct Current (BLDC) motors behavior. These motors are vastly used in electric vehicles, especially in Drones. The proposed approach is compared with the traditional Fast-Fourier Transform (FFT) and the experiments analyzing a BLDC motor of a drone demonstrates similar results but computationally simpler than that. The main contribution of this technique is the possibility to analyze signals in time domain, instead of the frequency domain. It is possible to identify working and faulty behavior with less computational resources than the traditional approach.

Nurses' turnover intention: The impact of leader-member exchange, organizational identification and job embeddedness.

The aim of this study was to examine the influence of three factors on turnover intention: leader-member exchange quality, organizational identification and job embeddedness. This area of inquiry has not been fully investigated in the literature. Employee turnover, particularly of professionals, becomes a very challenging issue. It continually affects organizations in terms of resourcing and developmental costs, manpower instability, day-to-day operations, perception of quality care and efficiency. Therefore, employees' working attitude and behaviour have drawn increasing attention for further research to determine which factors keep them with their employer. A cross-sectional survey was conducted with self-report questionnaires. Data were collected from 1,966 nurses from sixteen private general hospitals in Thailand during February-June 2016. Hypotheses were tested and analysed by means of a confirmatory factor analysis, structural equationmodelling and a bootstrapping procedure. The results revealed the direct relationship between leader-member exchange quality and job embeddedness. Organizational identification played an intermediary role that partially mediated the relationship between leader-member exchange quality on job embeddedness. Analysis also provided support for the mediating effect of organizational identification and turnover intention through job embeddedness. This study extends the job embeddedness theory and gains understanding of the antecedent factors that directly and indirectly cause employees to become embedded and lead to predict turnover intention. The findings are pertinent, as few studies have investigated such relationships. The implications provide insights into how organizations can better retain their workforce.

EMPLOYEE PERFORMANCE IMPROVEMENT MODEL BASED ON ISLAMIC WORK BEHAVIOR TO THE UMKM BATIK EMPLOYEES

This study aims to describe and analyze the effect of education, training and work experience on Islamic work behavior and its impact on human resource performance. The population used is employeesof batik UMKM in Central Java region. Based on the questionnaire distribution of 100 respondents, responded by the employees of 88 employees. The sampling technique is simple random sampling. Theanalysis tool is multiple linear regression, where previously tested the validity and reliability as well as the classical assumption test. The result of the test shows that education on Islamic work behavior shows a positive influence, it can be interpreted that the higher level of education owned by employees, it will increasingly increase the change of attitude and employee�s Islamic work behavior. Similarly,training and work experience also proved to have a positive effect on the behavior of Islamic work. Islamic behavior is proven to have a positive influence on the performance of human resources, can beinterpreted that the higher the ability of employees in making changes in attitudes and behavior of Islamic behavior, it will further improve the performance of human resources.Keywords: Education, training, work experience, Islamic work behavior and human resource performance

Exploring staff involvement in an organization development intervention in a school in the Kavango region, Namibia

The study is to explore staff involvement in organization development (OD) intervention in one of a rural junior secondary school in Kavango region, Namibia and aimed at determining the level of participation in change initiative and probing in participants’ perception and experience of the intervention process. In a democratic country such as Namibia every citizen is expected to bring change and participating in activities to improve their own institution for example School. It is a common practice among teachers of Ntokota School that they are passive to take action in change initiative for improving working relationship and Organization. This study introduced an OD intervention to a School in order to inspire the mindset of staff to be active in change initiative for School improvement by using bottom-up approach strategy of staff participation in series of activities that would enable them to improve and eventually moving the School to the intended goal. OD concept Model of seven steps was used for intervention and it is a participant driven that encourages staff to release their potential to initiate change for improvement. The study is located within qualitative interpretive and critical paradigm. Observation and semi-structured interviews were the main data collection tools used in the study. The researcher transcribed, grouped similar data into category, coded and translated data into a real meaning and identifies themes that address the research goal. The paper reveals that the absence of staff cooperation, involvement in the decision making processes, democratic leadership were the main factors perceived retarded the staff activeness in change initiative and participation. Staff viewed OD intervention as the most significance approach to change as it offers significant understanding and conception of change and embraced new approach of fostering democracy, inclusion of staff in the decision-making process, taking a decentralized decision and enhancing cooperation among staff. The study is of potential significance to educators and educational leaders to use OD approach for change to improve human working relationship and behavior in their own organization. It may motivate researchers to pursue OD studies and conduct OD projects with any organization of their choice.

On the Relation Between Teachers’ (In)formal Learning and Innovative Working Behavior: the Mediating Role of Employability

Teachers’ innovative work behavior and professional development is receiving more attention lately. More precisely, it is argued that teachers’ formal and informal learning is crucial to anticipate and deal with continuous changes and innovations in technology and didactics, for example. Therefore, this study researches the teachers’ innovative work behavior by studying relations between (in)formal learning activities, employability (i.e. five competences: occupational expertise, anticipation and optimization, personal flexibility, corporate sense and balance) and innovative working behavior (IWB, i.e. ideas generation, promotion and realization). Furthermore, the mediating role of employability between learning and innovative working behavior is studied, too. Based on path analysis conducted on questionnaire data from 301 primary and secondary school teachers from the French-speaking community of Belgium, findings conclude that employability competences are related to both formal and informal learning, but the relationship between informal learning and employability is stronger. Next, making a distinction between the frequency and use of social informal learning is relevant given the differentiated role the different components play. Feedback use in particular seems to play an important role in teachers’ employability and IWB. Finally, it can be concluded that employability partially mediates the relation between the undertaking of (in)formal learning activities and dimensions of innovative working behavior. Results imply that schools should pay more attention to supporting teachers’ informal learning since it’s crucial for improving their ability to innovate and to be able to deal with changes in the dynamic world of education.

Analysis of holographic polymer-dispersed liquid crystals (HPDLCs) for tunable low frequency diffractive optical elements recording

Holographic polymer dispersed liquid crystals (HPDLCs) are the result of the optimization of the photopolymer fabrication techniques. They are made by recording in a photopolymerization induced phase separation process (PIPS) in which the liquid crystal molecules diffuse to dark zones in the diffraction grating originated. Thanks to the addition of liquid crystal molecules to the composition, this material has a dynamic behavior by reorientation of the liquid crystal molecules applying an electrical field. In this sense, it is possible to use this material to make dynamic devices. In this work, we study the behavior of this material working in low frequencies with different spatial periods of blazed gratings, a sharp profile whose recording is possible thanks to the addition of a Holoeye LCoS-Pluto spatial light modulator with a resolution of 1920 × 1080 pixels (HD) and a pixel size of 8 × 8 μm2. This device allows us to have an accurate and dynamic control of the phase and amplitude of the recording beam.

Hot workability and microstructure evolution of the nickel-based superalloy Inconel 718 produced by laser metal deposition

The manufacturing of parts from nickel-based superalloys used to be dominated by conventional processes such as forging, which use expensive dies and require cost-intensive machining operations to produce the final part shape, due to the limited ability of the forging process to produce near-net shape parts. The ongoing efforts in developing additive manufacturing (AM) processes could promote an increasing competition of AM with traditional processes. AM offers various benefits such as near neat shaping, integration of functions into parts and the possibility to locally engineer components. However, manufacturing costs and process time in additive manufacturing rise rapidly with part size. For many applications, the disadvantages of AM and forging operations could be levered by mating both processes to new process chains. Adapted pre-forms for forging operations could be created by printing onto existing stock material, thus allowing to reduce the number of forging steps and to avoid high material waste. However, up to the present day, only very limited knowledge is available on the forming behavior of additively manufactured materials. In this paper, the hot deformation behavior and the associated microstructural changes of samples made from the nickel-based superalloy Inconel® 718 using laser metal deposition (LMD) have been studied using isothermal hot-compression tests. The as-built state is shown not to be suitable for hot working due to the presence of the Laves phase, which has to be removed by heat treatment. Wrought samples and heat-treated LMD samples are compared with respect to their hot working behavior. Pronounced shifts of characteristic points of the flow curves between both types of material are observed. The results show that heat-treated LMD samples are well hot workable, preferentially at higher values of the Zener-Hollomon parameter where incipient yield and initial work hardening occur at lower stress levels.

The THE EFFECT OF LEADERSHIP AND COMMUNICATION ON TEACHER WORK BEHAVIOR IN SDN BANJARBARU KALIMANTAN SELATAN

The purpose of this study is to determine the influence of leadership and communication on work behavior. The research method used is quantitative approach with survey method. Data collection techniques used questionnaires and interviews. Data analysis was done by using descriptive analysis and inferential analysis that is correlation analysis and regression analysis. The sample selected in this study amounted to 120 people from 172 teachers in Banjarbaru Selatan. The result is: (1) leadership has a strong relationship with work behavior, but does not give a direct influence on work behavior (2) communication has a very strong relationship and gives a direct influence on work behavior, (3) there is a positive influence between leadership and communication on the behavior of teachers SDN work in the city of Banjarbaru South Kalimantan. Therefore, it requires transparent and accountable leadership with open communication so as to encourage teachers to work more effectively.&#x0D; Keywords: Leadership, communication, work behavior

Pengaruh Motivasi terhadap Perilaku Kerja Petani Karet di Desa Puain Kanan Kecamatan Tanta Kabupaten Tabalong

This study aims to determine the effect of motivation on working behavior of rubber farmers, knowing the dominant motivation of rubber farmers, knowing the positive or negative relationship and the percentage of the influence of motivation on the working behavior of rubber farmers in the Puain Kanan Village, Tanta District, Tabalong Regency. The research method used is the case study method with data collection methods, namely the interview method. Data collection is carried out from May to August. The analysis used was qualitative analysis of rubber farmer's work behavior, power motivation, affiliate motivation and achievement motivation. Quantitative analysis uses multiple regression analysis with simultaneous testing, partial testing, correlation coefficient and coefficient of determination using SPSS 23 software for Windows. The results obtained showed that motivation influenced the working behavior of rubber farmers with Fcount 12, 470. Performance motivation variables were the biggest motivations that influenced the working behavior of rubber farmers with the highest tcount value of 3.005. Motivation of power, affiliation motivation and achievement motivation have a positive relationship to the working behavior of rubber farmers with a motivation variable contribution value of 51%.

Occupational safety across jobs and shifts in emergency departments in Denmark

This paper explores whether occupational safety and health (OSH) risk perceptions, behaviour and exposure differ among Emergency Department (ED) doctors, nurses and medical secretaries, and whether observed safe working conditions and behaviour in EDs vary across work shifts. Staff from four public hospital-based EDs completed a survey regarding safety climate, risk behavior, work pressure, exposure to and reporting of injuries, violence and threats. Furthermore, safety observations of working conditions (e.g. order and tidiness) and behavior (e.g. discarding hypodermic needles) were carried out during day, evening and night shifts. Rates of self-reported violence and threats in ED doctors and nurses were two to three times greater than rates seen for doctors and nurses at hospitals in general. However, ED respondents perceived a greater managerial focus on certain aspects of the safety climate. Work pressure and lack of time (among doctors and nurses) and social pressure (among medical secretaries) were the primary reasons given for taking OSH risks. If OSH incidents (e.g. injuries or violence) were not reported, it was often because the process was perceived as too laborious, and some incidents were considered ‘part of the job’. Observations of order and tidiness in the EDs showed a gradual lower score in safety conditions from the day to the evening and night shift. Multifaceted and integrated interventions for educating and training ED personnel need to take into account their varying risk exposures, perceptions and behaviors in creating and sustaining an efficient, safe and healthy working environment.

Differences in agricultural activities related to incidence of scrub typhus between Korea and Japan.

OBJECTIVESThe purpose of this study was to establish a basis for improving or strengthening the preventive strategy against scrub typhus in Korea by comparing and analyzing the difference of prevention behaviors contributing to the occurrence of scrub typhus in Japan and Korea.METHODSThe survey was carried out in Jeollabuk-do, which is a high risk and high incidence area, and Fukuoka Prefecture, which is a high risk and low incidence area. The study included 406 Korean farmers and 216 Japanese farmers. Data were collected through face-to-face surveys by interviewers who had completed standardized education.RESULTSKorean farmers have a higher percentage of agricultural working posture that involved contact with weeds than Japanese farmers (p<0.05). The frequency and proportion of weeding were lower in Korean farmers than in Japanese farmers (p<0.05). The level of knowledge about scrub typhus was significantly higher among Korean farmers than among Japanese farmers (p<0.05). Mostly, the behavior of agriculture work was more appropriate for Japanese farmers than for Korean farmers (p<0.05). The total average level of agricultural work was lower in Korea than in Japan, lower in men than women, and lower in part-time farmers than full-time farmers (p<0.05).CONCLUSIONSThis study suggests that it is reasonable to develop and provide a program that can improve the level of preventive behavior taking into consideration the characteristics of the subject in order to reduce the incidence of diseases in high-risk areas for scrub typhus.

Electrical behaviour of the pump working as turbine in off grid operation

The use of pumps working as turbines (PATs) connected to the electric system, in the replacement of pressure reduction valves to reduce the excessive pressure in water distribution networks, have been studied for the last years. The introduction of PATs is very important in the water-energy nexus to promote the increase of the energy savings. As consequence, the majority of the water systems does not have access to the electrical grid and, therefore, the need to study the PATs operation off-grid is necessary. In this line, the novelty of this research is the application and optimization of a PAT in water systems when the recovery solution is off-grid type. To operate correctly, the induction machine requires an external source of reactive power, which is typically provided by the electrical grid. To supply the required reactive power, a bank of capacitors is installed at the machine terminals, so-called self-excited induction generator (SEIG). The analytical model, simulation and experimental works were performed, to analyse the SEIG behaviour. The results were applied in a SEIG-PAT system obtaining the global efficiency of the system for different speeds and loads. The global efficiency decreases 47% when off-grid operation, showing the need to optimize the electrical parameters of the generator to operate as off- grid with acceptable efficiency levels. In this framework, a tuning methodology for the SEIG capacitor bank values was developed to be automatically adjusted according to the operating point of the PAT to maximize its efficiency.