Initial stage oxidation of cr in dry and wet environment at 1073 K and the significant differences of FT – IR spectra produced thereof

Little information has been known on the initial – stage oxidation if there is water vapor involved. Cr samples of 10 mm × 10 mm × 1 mm were isothermally oxidized in dry and wet environment respectively for 86.4 ks. Compact and even surface of Cr2O3 was formed on samples oxidized in dry environment. However, the ability to form compact and even Cr2O3 was retarded in wet environment. XRD analysis on all samples shows that Cr2O3 can be formed in dry and wet environment. The IR transmission spectra for samples oxidized in dry environment, were consisting of more intense peak while samples oxidized in wet environment has more relaxed peak. Moreover the peak of samples oxidized in dry tends to be narrower, while samples oxidized in wet tend to have broader peak

Observation on void formed in oxide scale of Fe-Cr-Ni alloy at 1073K in dry and humid environments

Void formation in oxide scale during high temperature oxidation is a common phenomenon. Over a long period of time voids will affect the mechanical property of scales by influencing the cracking and spalling. Voids formed in dry environment are different than that of formed in humid environment. With the presence of water vapor in humid environment the formation of void will increase, thus greater number of void compared to that in dry environment. Fe-Cr-Ni alloy samples were exposed isothermally at 1073 K in air (P_(O_2)= 0.21atm = 2.1 x? 10 5 Pa) and humid (air + steam) environments. XRD analysis done to all samples confirms that Fe2O3, Fe3O4, NiCr2O4, FeCr2O4, Cr2O3 and NiO phases exist in the scale. EDX analysis done shows varying compositions of Fe,Cr,Ni and O in outer and inner oxide scale, oxide scale/metal interface and metal. Field emission scanning electron microscope (FE-SEM) was used to investigate voids formed in the cross sections of the oxidized samples. Volume fraction of voids in the oxide scale was calculated in accordance to the cross sectional area fraction of voids in the scale. It shows that Fe-Cr-Ni alloy samples exposed in humid environment has as high as 71% more voids than that exposed in dry environment. It is concluded that the humid environment increased the number of void formed in the oxide scale, thus facilitates the exfoliation of protective scale during the high temperature oxidation

Observation On Void Formed In Oxide Scale Of Fe-Cr-Ni Alloy At 1073k In Dry And Humid Environments

Void formation in oxide scale during high temperature oxidation is a common phenomenon. Over a long period of time voids will affect the mechanical property of scales by influencing the cracking and spalling. Voids formed in dry environment are different than that of formed in humid environment. With the presence of water vapor in humid environment the formation of void will increase, thus greater number of void compared to that in dry environment. Fe-Cr-Ni alloy samples were exposed isothermally at 1073 K in air (P_(O_2 )= 0.21atm = 2.1×?10?^(5 )Pa) and  humid (air + steam) environments. XRD analysis done to all samples confirms that Fe2O3, Fe3O4, NiCr2O4, FeCr2O4, Cr2O3 and NiO phases exist in the scale. EDX analysis done shows varying compositions of Fe,Cr,Ni and O in outer and inner oxide scale, oxide scale/metal interface and metal. Field emission scanning electron microscope (FE-SEM) was used to investigate voids formed in the cross sections of the oxidized samples. Volume fraction of voids in the oxide scale was calculated in accordance to the cross sectional area fraction of voids in the scale. It shows that Fe-Cr-Ni alloy samples exposed in humid environment has as high as 71% more voids than that exposed in dry environment. It is concluded that the humid environment increased the number of void formed in the oxide scale, thus facilitates the exfoliation of protective scale during the high temperature oxidation. ABSTRAK: Pembentukan gelembung udara di dalam lapisan oksida ketika proses pengoksidaan di suhu tinggi merupakan satu fenomena biasa. Pada satu jangka masa yang panjang gelembung-gelembung ini akan memberi kesan kepada sifat mekanikal oksida dengan mempengaruhi pembentukan keretakan dan pengelupasan oksida. Gelembung udara yang terbentuk di dalam persekitaran kering berbeza daripada yang terbentuk di dalam persekitaran lembap. Dengan adanya wap air, pembentukan gelembung akan bertambah berbanding yang terbentuk di dalam persekitaran kering. Sampel aloi Fe-Cr-Ni telah dioksidakan secara isoterma pada suhu 1073 K di dalam udara (P_(O_2 )= 0.21atm = 2.1×?10?^(5 )Pa) dan lembap (udara + wap air). Analisis Pembelauan Sinar – X (XRD) kepada semua sampel menunjukkan oksida yang terbentuk ialah Fe2O3, Fe3O4, NiCr2O4, FeCr2O4, Cr2O3 dan NiO. Analisis Penyebaran Tenaga Sinar – X (EDX) menunjukkan komposisi Fe, Cr, Ni dan O yang berubah - ubah di lapisan oksida luar dan dalam, oksida/ antara muka logam dan logam. Mikroskop Imbasan Elektron-Pancaran Medan (FE-SEM) digunakan untuk meneliti gelembung di dalam oksida pada keratan rentas sampel. Pecahan isi padu gelembung yang terbentuk pada oksida dikira dengan merujuk kepada pecahan luas keratan rentas pada oksida tersebut. Sampel aloi Fe-Cr-Ni yang dioksidakan di dalam persekitaran lembap mempunyai kandungan gelembung udara 71% lebih banyak berbanding dengan yang dioksidakan di dalam persekitaran kering. Kesimpulannya persekitaran lembap meningkatkan bilangan gelembung yang terbentuk di dalam lapisan oksida, sekaligus memudahkan pengelupasan oksida semasa pengoksidaan suhu tinggi. KEYWORDS: high temperature oxidatio;, Fe-Cr-Ni alloy; void formation; quantitative analysis of voi;, dry environment; humid environmen

Colorectal Cancer: A Review of Carcinogenesis, Global Epidemiology, Current Challenges, Risk Factors, Preventive and Treatment Strategies

Colorectal cancer (CRC) is the second most deadly cancer. Global incidence and mortality are likely to be increased in the coming decades. Although the deaths associated with CRC are very high in high-income countries, the incidence and fatalities related to CRC are growing in developing countries too. CRC detected early is entirely curable by surgery and subsequent medications. However, the recurrence rate is high, and cancer drug resistance increases the treatment failure rate. Access to early diagnosis and treatment of CRC for survival is somewhat possible in developed countries. However, these facilities are rarely available in developing countries. Highlighting the current status of CRC, its development, risk factors, and management is crucial in creating public awareness. Therefore, in this review, we have comprehensively discussed the current global epidemiology, drug resistance, challenges, risk factors, and preventive and treatment strategies of CRC. Additionally, there is a brief discussion on the CRC development pathways and recommendations for preventing and treating CRC. View Full-Tex

Mitigation of Cr2_{2}O3_{3}’s reduction by MnO in UHV and oxidising environments at 500°C and 700°C : an observation of initial oxidation of Fe-Cr alloy with in-situ X-ray photoelectron spectroscopy

This work is on the understanding of the oxidation mechanism of Fe-Cr alloys, the Crofer 22 APU alloy. This alloy is designed for interconnector part of a planar Solid Oxide Fuel Cell System which subjects the alloy to gaseous environments (O2, H2, H2O and CO) at temperatures from 500 to 750 °C. The evaporation of Cr causes corrosion from the alloy during SOFC’s operation. The critical information on the mechanism of Cr evaporation lies on in-situ observation of the alloy’s initial oxidation. This work is using the in-situ X-ray Photoelectron Spectroscopy (XPS) to understand the mechanism by utilising the ability of XPS to probe (up to 5 nm) of the outer alloy's surface in which initial oxidation reaction occurs. This work involves two XPS instruments with different capabilities. The first instrument: PHI Versa Probe has enabled the measurements in UHV which representing a low oxygen partial pressure (low ${P_{O_2}}$) environment. The second instrument: ScientaOmicron has enabled the measurements in O2 which representing the high oxygen partial pressure (high ${P_{O_2}}$) environment.The first experimental part is on the observation of the behaviour of high- purity Fe and Cr in UHV for 500 °C and 700 °C. Subsequently, Fe-22Cr model alloy is also investigated in UHV at the same temperatures to rule out the behaviour that might only be observed on commercial Fe-Cr alloy Crofer 22 APU. In such environments, Fe’s surface is being reduced from oxide into metallic while Cr exists as both metal and oxide. Model sketches are suggested based on the outcomes of these in-situ observations in UHV. This experiment has provided a base on understanding the behaviour of Crofer 22 APU alloy in the same conditions and further for the measurements done at high ${P_{O_2}}$. Second experimental part embarks on the investigation of Crofer 22 APU alloy in UHV for 500 °C and 700 °C. Being a commercial alloy, while it has the same amount of Fe and Cr as in Fe-22Cr model alloy, Crofer 22 APU has some other minor elements added up to 0.005 wt.%. These minor elements particularly Mn and Ti affects the behaviour of Fe and Cr at high-temperature. While studies have acknowledged the effect of these minor elements but not all of them have been able to describe the mechanism. Due to the low ${P_{O_2}}$ environment provided by the UHV, coupled with the presence of Mn and Ti has an influence on the selective oxidation behaviour of Cr. This is an evidence of the role of Mn and Ti in regulating the formation of Cr oxidation in such environment.The third experimental part is the highlight of the work because the AP-XPS has allowed for the observation of the oxidation mechanism on Crofer 22 APU in high p_(O_2 ) environment. The oxidation mechanism behaviour differs in higher ${P_{O_2}}$ environment. This chapter showcases the first result on in-situ XPS measurements employing AP-XPS at temperatures of 500 °C and 700 °C on Crofer 22 APU. The measurements, with ${P_{O_2}}$=5 mbar for 500 °C and 700 °C, has demonstrated the significant roles of Mn in regulating the oxidation of Cr.Oxidation mechanism of alloy has been investigated in-situ with both UHV- and AP-XPS to provide a means of low and high ${P_{O_2}}$ environments at 500 °C and 700 °C. The outcome from different environments provided has been different from each other. Nevertheless, it could provide a foundation for a systematic study with in-situ XPS on the initial oxidation mechanism of high-temperature alloy in the future

APPLICATION OF RISK MANAGEMENT AND TIME STUDY TO TOTAL COMPENSATION DESIGN: CASE STUDY OF FA BERSAUDARA AS PARTNER OF LG ELECTRONIC INDONESIA

Abstract.  LG Electronic Indonesia (LGEI), one of popular electronics brand in Indonesia created a new system in aftersales service section. The new system is making the aftersales divisions separated from LG Electronic Indonesia and it is handled now by a third party as Authorized Service Center (ASC). In this current conditions, FA Bersaudara has many service delays in every month that could not be finished. From the early research showing the employees unsatisfied with current compensation design system. So that, this research is provided to design the compensation system especially cash compensation that could increase the employees’ satisfaction with time study and risk management approach. Time study is being focused on because this theory is giving more fairness with detained compensation based on level of job. The risk management will focus on the cost that can be maintained by company to pay to employees as the part of the total compensation. This research use the Microsoft excel as software to calculating the number of standard time and also expected value from risks. From this research, it can be concluded that the total compensation is based on basic salary, fuel and food compensation, working time and other related risks. These factors may be different with prior compensation system which compensation is solely based on two factors which are basic salary and fuel and food compensation with no regards of working time and other related risks. There is significant difference between compensation system with standardized time calculation and risk and compensation system with no consideration in calculating related risk and standardized working time. The cost that raised from risk adjustment can be mitigated by using non-insurance transfer and insurance methods. Keywords: compensation, time study, risk managemen

Studies on initial stage of high temperature oxidation of Fe - 9 to 12% Cr alloys in water vapour environment

Fe - 9 to 12%Cr alloys are a material for the thick sections boiler components and steam lines of a power plant. The role Fe - 9 to 12%Cr alloys is becoming more prominent in the development of a new generation of Ultra-Supercritical (USC) Power Plant due to the target operating temperature is reaching 620 °C (893 K), in 100% steam condition as well as pressure in excess of 300 bar (30 × 106 Pa). In such condition, the integrity of Fe - 9 to 12%Cr alloys relies on the oxide scale formed during the time of exposure. However due to the high temperature and water vapor condition, it is a well known fact that, the formation of oxide scale is accelerated thus depleting the structural integrity of the Fe - 9 to 12%Cr alloys over the time. Studies show that not only the formation of protective oxide scale was suppressed but the formation of non-protective oxide scale was accelerated instead. Decades of studies done by various groups around the globe has yet to have consensual on the exact mechanism of this phenomenon. Initial stage oxidation of these alloys plays great roles in hope to understand the formation of oxide scale in water vapor condition at high temperature. This paper reviews previous research works to understand the initial stage oxidation of Fe - 9 to 12%Cr alloys at high temperature in water vapor condition