Assessing phase discrimination via the segmentation of an elemental energy dispersive X-ray spectroscopy map: A case study of Bi2Te3 and Bi2Te2S

The present case study critically assesses the efficacy of a previously proposed segmentation methodology as a means to discriminate phases via post-processing the image of an elemental map. In the Bi2Te2.5S0.5 multiphase compound, the reference spectra of the Bi2Te3 and Bi2Te2S phases are distinct enough to effectively distinguish two phases during map acquisition. Since the counts of the sulphur-K peak in the X-ray emission data are significantly higher for Bi2Te2S compared to Bi2Te3, the segmentation methodology exploits this variation and enables successful phase discrimination via post-processing the image of the elemental map

Rapid fabrication of diffusion barrier between metal electrode and thermoelectric materials using current-controlled spark plasma sintering technique

A continuous, stable diffusion barrier between PbTe thermoelectric material and Ni conducting electrode was generated using the current-controlled spark plasma sintering technique. This new method creates a diffusion barrier layer by utilising the melt generated in the area of contact between components, also called the weld nugget in a resistance spot welding process. The current-controlled spark plasma sintering process bonds the solid workpieces in a fraction of the time required to fabricate interphase layers using powder components with the common temperature-controlled spark plasma sintering. The substantially reduced time of bonding compared to previous methods is beneficial to the thermoelectric properties of materials due to their limited exposure to high temperatures, which occasionally are much higher than the operating temperatures of devices. This work introduces a rapid and efficient bonding technique that can be applied to a wide variety of materials

Diabetes and all-cause mortality, a 18-year follow-up study

This study compared mortality rates and decline in life expectancy of Iranian patients with type 2 diabetes (T2DM) with the general population. A retrospective study of 2451 patients with T2DM was conducted in the Isfahan Endocrine and Metabolism Research Center, Iran, between 1992 and 2010. The mean (SD) of diabetes duration and median (Q1,Q3) of follow-up period were 15.5(8.0) and 8(5, 10) years. The main outcome was all-cause mortality. 732(29.87%) of patients died during the follow-up. Overall mortality rates (95%CI) per 1000 person-years in men and women were 56.3(52.0-62.1) and 27.3(24.5-30.4), respectively. The relative risks (95%CI) of all-cause mortality in males vs. females with T2DM aged 45-49, 50-54, 55-59, 60-64, 65-69, 70-74 were [3.02(1.49-6.11) vs. 2.09(0.96-4.57)], [4.05(2.73-6.01) vs. 2.29(1.52-3.45)], [4.13(3.26-5.24) vs. 1.70(1.23-2.35)], [2.42(1.90-3.07) vs. 1.82(1.46-2.27)], [2.36(2.02-2.76) vs. 1.49(1.25-1.78)] and [1.71(1.50-1.95) vs. 1.04(0.88-1.23)] times more than the general population, respectively. Men and women living with diabetes lost an average of 13.2(6.3) and 13.9(6.0) life-years from the year of diagnosis, respectively (p = 0.101). The estimated life-years lost were greater in younger patients and a gradual decline was observed with increasing the age at diagnosis. In conclusion, Iranians with diabetes had higher risk of death and lower life expectancy compared to the general population

The effect of foamy slag in electric arc furnaces on electric energy consumption

In electric arc furnace steelmaking units, the essential parameters that considered important are reducing price, increasing production and decreasing environmental pollution. Electric arc furnaces are the largest users of electric energy in industry. The most important techniques that can be used to reduce the electric energy consumption in electric arc furnaces are scrap preheating, stirring, use of burners and hot charge and foamy slag. Between these methods, use of foamy slag is the most useful and economic factor. Foamy slag can reduce the amount of energy, electrods, refractory consumption, tap to tap time and increases productivity. In this research, method of production and optimum conditions for foamy slag in 200 tons electric arc furnace were investigated. The use of foamy slag in this research shows that it can reduce the electric energy consumption from 670 to 580 kwh/ton and also the melting time from 130 to 115 min. and the electric power input can be increase with foamy slag. It also shows that with foamy slag the optimum amount of FeO in slag is 20-24 percent and the optimum basicity is 2-2.2

Cross-sectional and longitudinal assessments of risk factors associated with hypertension and moderately increased albuminuria comorbidity in patients with type 2 diabetes: a 9-year open cohort study.

Background: Moderately increased albuminuria (MIA) is strongly associated with hypertension (HTN) in patients with type 2 diabetic mellitus (T2DM). However, the association between risk factors and coexisting HTN and MIA remains unassessed. Objectives: This study aimed to determine both cross-sectional and longitudinal associations of risk factors with HTN and MIA comorbidity in patients with T2DM. Methods: A total of 1,600 patients with T2DM were examined at baseline and longitudinal data were obtained from 1,337 T2DM patients with at least 2 follow-up visits to assess the presence of HTN alone (yes/no), MIA alone (yes/no) and the coexistence of both (yes/no) in a 9-year open cohort study between 2004 and 2013. Bivariate mixed-effects logistic regression with a Bayesian approach was employed to evaluate associations of risk factors with HTN and MIA‎ comorbidity in the longitudinal assessment. Results: After adjustment for age and BMI, patients with uncontrolled plasma glucose, as a combined index of the glucose profile, were more likely to have HTN [odds ratio (OR): 1.73 with 95% Bayesian credible intervals (BCI) 1.29-2.20] and MIA [OR: 1.34 (‎95% BCI 1.13-1.62)]. The risks of having HTN and MIA were increased by a one-year raise in diabetes duration [with 0.89 (95% BCI 0.84-0.96) and 0.81 (95% BCI 0.73-0.92) ORs, respectively] and a one-unit increase in non-high-density lipoprotein-cholesterol (Non-HDL-C) [with 1.30 (95% BCI 1.23-1.34) and 1.24 (95% BCI 1.14-1.33) ORs, respectively]. Conclusions: T2DM patients with HTN,‎ MIA, and the coexistence of both had uncontrolled plasma glucose, significantly higher Non-HDL-C, and shorter diabetes duration than the other T2DM patients. Duration of diabetes and uncontrolled plasma glucose index showed the stronger effects on HTN and MIA comorbidity than on each condition separately

Prevalence of Goitre in Isfahan, Iran, Fifteen Years After Initiation of Universal Salt Iodization

This cross-sectional study investigated the prevalence of goitre in Isfahan, a centrally-located city in Iran, 15 years after the initiation of universal salt iodization. In total, 2,523 Isfahani adults (1,275 males, 1,248 females) aged >20 years were selected by multi-stage cluster-sampling method. Goitre rate, serum thyroid-stimulating hormone (TSH), thyroxine (T4), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), and urinary iodine concentration (UIC) were measured and compared between the goitrous (n=478) and the non-goitrous (n=2,045) participants. The total goitre rate was 19% (n=478) of the 2,523 adults. The rate of Grade I and II goitre was 12.4% (n=312) and 6.6% (n=166) respectively. The total goitre rate, Grade I and II goitre were more prevalent among women than among men. Hypothyroidism was observed in 6.4% (130/2,045) and 18.6% (89/478) of the non-goitrous and goitrous participants respectively [odds ratio (OR)=3.6, 95% confidence interval (CI) 2.7-4.9, p=0.001]. Hyperthyroidism was present in 0.8% (17/2,045) and 5.2% (29/478) of the non-goitrous and goitrous adults respectively (OR=9.0, 95% CI 4.9-16.6, p=0.001). Hypothyroidism was more prevalent in Grade II than in Grade I goitre and among those without goitre (31.3%, 14.1%, and 6.4% respectively) (p=0.001). Positive TPOAb was observed in 24% (n=50) of the non-goitrous and 33.5% (n=84) of the goitrous subjects (p=0.03). Positive TPOAb was observed in 24.6% (35 of 142) of the Grade I and 45% (49 of 109) of the Grade II goitrous adults (p=0.001). Positive TgAb was observed in 21.6% (n=45) of the non-goitrous and 35.9% (n=90) of the goitrous adults (p=0.001). Positive TgAb was observed in 30.3% (43 of 142) of the Grade I and 43.1% (47 of 109) of the Grade II goitrous adults (p=0.04). The median UIC was 18 μg/dL (range 1-80 μg/dL). It was 17.9 μg/dL and 19 μg/dL in the non-goitrous and goitrous adults respectively. After 15 years of successful universal salt iodization in Isfahan, goitre is still endemic, which may be due to thyroid autoimmunity. However, other environmental or genetic factors may have a role

Preparation of n-type Bi2Te3 Films by Electrophoretic Deposition

A high quality crack-free film of Bi2Te3 material has been deposited for the first time using electrophoretic deposition (EPD) and microstructures of various films have been investigated. One of the most important thermoelectric (TE) applications is Bi2Te3 to manufacture TE generators (TEG) which can convert waste heat into electricity targeting the global warming issue. However, the high cost of the manufacturing process of TEGs keeps them expensive and out of reach for commercialization. Therefore, utilizing EPD as a simple and cost-effective method will open new opportunities for TEG’s commercialization. This method has been recently used for advanced materials such as microelectronics and has attracted a lot of attention from both scientists and industry. In this study, the effect of media of suspensions has been investigated on the quality of the deposited films as well as their microstructure. In summary, finding an appropriate suspension is a critical step for a successful EPD process and has an important effect on both the film’s quality and its future properties

Solid-state bonding of bulk PbTe to Ni electrode for thermoelectric modules

The efficiency of thermoelectric generators is defined by the thermoelectric performance of materials, as expressed by the thermoelectric figure-of-merit, and their contacts with electrodes. Lead chalcogenide thermoelectric materials, and in particular PbTe, perform well in the 500 - 900 K temperature range. Here, we have successfully bonded bulk PbTe to Ni electrode to generate a diffusion barrier, avoiding continuous reaction of the thermoelectric legs and conducting electrodes at the operating temperature. We have modified the commonly used spark plasma sintering assembly method to join Ni electrode to bulk PbTe by driving the total supplied electrical current through the Ni and PbTe solid interfaces. This permits the formation of a thin diffusion layer, roughly 4.5 µm in thickness, which is solely comprised of nickel telluride. This new technique towards the bonding of PbTe with the electrode is beneficial for thermoelectric materials, since high temperatures have proven to be damaging to the quality of bulk material. The interphase microstructure, chemical composition, and crystallographic information were evaluated by a scanning electron microscope equipped with electron back-scattered diffraction analysis. The obtained phase at the Ni/PbTe contact is found to be β2 Ni3±xTe2 with a basic tetragonal crystallographic structure of the defective Cu2Sb type

Thermoelectric performance of electrophoretically deposited p-type Bi2Te3 film

In this study, p-type Bi2Te3 films were fabricated using a fast, cost-effective, electrophoretic deposition method for thermoelectric applications. The sintering process was carried out at 693K, which resulted in compact, dense coatings. SEM investigations showed the uniform and even thicknesses across the green and sintered films. In addition, their microstructures were examined in more depth. Furthermore, the Seebeck coefficient measurements of the green and sintered films were compared and the highest in-plane Seebeck coefficients of 239μV/K have been recorded for the sintered film at 500 K

Suspension characteristics and electrophoretic deposition ofp-Type Bi2Te3Films for thermoelectric applications

Electrophoretic deposition (EPD) was utilized to prepare uniform crack-free Bi2Te3 films for thermoelectric applications effectively. A p-type Bi2Te3 film with a coherent structure and even thickness was deposited from Tetrahydrofuran (THF) suspensions and examined using a scanning electron microscope (SEM). The specific weights of the depositions, the effective percentile coverage of the films on the substrate, the zeta potential and the electrical conductivity of different suspensions and the in-plane Seebeck coefficients of the Bi2Te3 films were measured. Although the Seebeck coefficient value of the EPD film (126 μV/K) was approximately 25% lower than the highest value reported for Bi2Te3 in the open literature via the co-sputtering method (160 μV/K), one of the most complex and expensive routes, the cost-effectiveness and speed of the simple EPD process is an undeniable advantage. This could open up new opportunities in the application of films to commercialize thermoelectric generators (TEG). It is interesting to note that the value of the Seebeck coefficient for our EPD-fabricated film was higher than for some of the other types of coatings prepared via more expensive and sophisticated fabrication routes, such as the electrodeposition technique (80 μV/K), for example