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Oral History Interview with Ali H. Heidari, April 20, 2011
No full textInterview with Ali Heidari, an Iranian immigrant, realtor, and restaurateur from Tehran. Heidari discusses growing up, education, moving to Athens, Texas in 1975, attending UT Arlington, getting into real estate, his family, his reaction to the 1979-81 hostage crisis, experiences as an immigrant in DFW, and his thoughts on American youth and culture
Hydrogen reduction of industrial iron ore pellets : a multi-scale study from surface to core
No full textAbstract
The transition towards sustainable ironmaking necessitates the replacement of carbon-based reduction processes with hydrogen-based alternatives to mitigate CO₂ emissions. This study investigates the reduction behavior of two types of industrial pellets utilized in direct reduction (DRI) and blast furnaces (BFs), using hydrogen (H₂) and carbon monoxide (CO) as reducing agents. The experimental analysis utilizes ambient pressure X-ray photoelectron spectroscopy (APXPS) to examine the surface reduction mechanisms and a thermogravimetric analysis (TGA) to evaluate kinetic parameters in bulk scale.
DRI pellets achieved a higher metallization degree during surface reduction by hydrogen due to their higher porosity. Although adding CO to the reducing gas hindered the formation of metallic iron in DRI pellet, BF pellet reached to 20% metallization degree by a mixture of 50:50 CO:H₂. However, subsequent reoxidation of the reduced iron to wüstite and magnetite occurred due to increasing partial pressure of H₂O and CO₂ on the surface of the pellets.
Investigating the effect of water vapor on the hydrogen reduction of pellets showed that although complete reduction is thermodynamically possible with 30% water vapor in the system, the reduction of wüstite to iron could not start, even at high temperatures, due to a kinetic barrier. The effect of 20% water vapor on the reduction degree was dependent on the reduction temperature. Although adding 10% water vapor decreased the rate of reduction, it did not affect the reduction degree. Original papers Heidari, A., Niknahad, N., Iljana, M., & Fabritius, T. (2021). A review on the kinetics of iron ore reduction by hydrogen. Materials, 14(24), 7540. https://doi.org/10.3390/ma14247540 https://doi.org/10.3390/ma14247540 Self-archived version Heidari, A., Ghosalya, M. K., Alaoui Mansouri, M., Heikkilä, A., Iljana, M., Kokkonen, E., Huttula, M., Fabritius, T., & Urpelainen, S. (2024). Hydrogen reduction of iron ore pellets: A surface study using ambient pressure X-ray photoelectron spectroscopy. International Journal of Hydrogen Energy, 83, 148–161. https://doi.org/10.1016/j.ijhydene.2024.08.094 https://doi.org/10.1016/j.ijhydene.2024.08.094 Self-archived version Heidari, A., Heikkilä, A., Iljana, M., & Fabritius, T. (2024). A comparison between the reduction behavior of DRI and BF pellets in H2 and CO atmospheres. Journal of Sustainable Metallurgy, 10(4), 2068–2084. https://doi.org/10.1007/s40831-024-00951-x https://doi.org/10.1007/s40831-024-00951-x Self-archived version Heidari, A., Ilmakangas, T., Pöyhtäri, S., Heikkinen, E. P., Sulasalmi, P., & Fabritius, T. (in press). The influence of water vapor on hydrogen reduction of iron ore pellets. Ironmaking & Steelmaking. Tiivistelmä
Siirtyminen kestävään raudanvalmistukseen edellyttää hiilipohjaisten pelkistysprosessien korvaamista vetyyn perustuvilla vaihtoehdoilla hiilidioksidipäästöjen vähentämiseksi. Tämä tutkimus tarkastelee kahden teollisen pellettityypin pelkistymiskäyttäytymistä suorapelkistyksessä (DRI) ja masuunissa (BF) käyttäen pelkistimenä vetyä (H₂) ja hiilimonoksidia (CO). Kokeellinen analyysi hyödyntää painetta kontrolloivaa röntgenfotoelektronispektroskopiaa (APXPS) pinnan pelkistysmekanismien tutkimiseen sekä termogravimetristä analyysia (TGA) kineettisten parametrien arviointiin suuremmassa mittakaavassa.
Tutkittaessa pinnan pelkistymistä vedyllä DRI-pelletti saavutti korkeamman metallisaatioasteen verrattuna BF-pellettiin, mikä johtui sen suuremmasta huokoisuudesta. Metallista rautaa ei muodostunut DRI-pelletissä, kun pelkistyskaasuun vedyn lisäksi lisättiin hiilimonoksidia. Kuitenkin BF-pelletti saavutti korkeamman metallisaatioasteen (20 %), kun pelkistyskaasujen suhde oli 50:50. Pelkistyneen raudan uudelleenhapettumista wüstiitiksi ja magnetiitiksi havaittiin tapahtuvan, kun H₂O- ja CO₂-osapaineet kasvoivat pelletin pinnalla.
Tutkittaessa vesihöyryn vaikutusta pelletin vetypelkistyksen aikana havaittiin, että vaikka täydellinen pelkistyminen on termodynaamisesti mahdollista vesihöyrypitoisuuden ollessa 30 %, wüstiitin pelkistyminen raudaksi ei tapahdu edes korkeissa lämpötiloissa kineettisten esteiden takia. Vesihöyrypitoisuuden ollessa 20 % pelkistymiseen vaikutti myös käytetty pelkistyslämpötila. Vaikka 10 prosentin vesihöyrypitoisuus hidasti pelkistysnopeutta, se ei vaikuttanut pelkistysasteeseen. Osajulkaisut Heidari, A., Niknahad, N., Iljana, M., & Fabritius, T. (2021). A review on the kinetics of iron ore reduction by hydrogen. Materials, 14(24), 7540. https://doi.org/10.3390/ma14247540 https://doi.org/10.3390/ma14247540 Rinnakkaistallennettu versio Heidari, A., Ghosalya, M. K., Alaoui Mansouri, M., Heikkilä, A., Iljana, M., Kokkonen, E., Huttula, M., Fabritius, T., & Urpelainen, S. (2024). Hydrogen reduction of iron ore pellets: A surface study using ambient pressure X-ray photoelectron spectroscopy. International Journal of Hydrogen Energy, 83, 148–161. https://doi.org/10.1016/j.ijhydene.2024.08.094 https://doi.org/10.1016/j.ijhydene.2024.08.094 Rinnakkaistallennettu versio Heidari, A., Heikkilä, A., Iljana, M., & Fabritius, T. (2024). A comparison between the reduction behavior of DRI and BF pellets in H2 and CO atmospheres. Journal of Sustainable Metallurgy, 10(4), 2068–2084. https://doi.org/10.1007/s40831-024-00951-x https://doi.org/10.1007/s40831-024-00951-x Rinnakkaistallennettu versio Heidari, A., Ilmakangas, T., Pöyhtäri, S., Heikkinen, E. P., Sulasalmi, P., & Fabritius, T. (in press). The influence of water vapor on hydrogen reduction of iron ore pellets. Ironmaking & Steelmaking. Academic dissertation to be presented with the assent of the Doctoral Programme Committee of Technology and Natural Sciences of the University of Oulu for public defence in the Oulun Puhelin auditorium (L5), Linnanmaa, on 29 August 2025, at 12 noonAbstract
The transition towards sustainable ironmaking necessitates the replacement of carbon-based reduction processes with hydrogen-based alternatives to mitigate CO₂ emissions. This study investigates the reduction behavior of two types of industrial pellets utilized in direct reduction (DRI) and blast furnaces (BFs), using hydrogen (H₂) and carbon monoxide (CO) as reducing agents. The experimental analysis utilizes ambient pressure X-ray photoelectron spectroscopy (APXPS) to examine the surface reduction mechanisms and a thermogravimetric analysis (TGA) to evaluate kinetic parameters in bulk scale.
DRI pellets achieved a higher metallization degree during surface reduction by hydrogen due to their higher porosity. Although adding CO to the reducing gas hindered the formation of metallic iron in DRI pellet, BF pellet reached to 20% metallization degree by a mixture of 50:50 CO:H₂. However, subsequent reoxidation of the reduced iron to wüstite and magnetite occurred due to increasing partial pressure of H₂O and CO₂ on the surface of the pellets.
Investigating the effect of water vapor on the hydrogen reduction of pellets showed that although complete reduction is thermodynamically possible with 30% water vapor in the system, the reduction of wüstite to iron could not start, even at high temperatures, due to a kinetic barrier. The effect of 20% water vapor on the reduction degree was dependent on the reduction temperature. Although adding 10% water vapor decreased the rate of reduction, it did not affect the reduction degree.Tiivistelmä
Siirtyminen kestävään raudanvalmistukseen edellyttää hiilipohjaisten pelkistysprosessien korvaamista vetyyn perustuvilla vaihtoehdoilla hiilidioksidipäästöjen vähentämiseksi. Tämä tutkimus tarkastelee kahden teollisen pellettityypin pelkistymiskäyttäytymistä suorapelkistyksessä (DRI) ja masuunissa (BF) käyttäen pelkistimenä vetyä (H₂) ja hiilimonoksidia (CO). Kokeellinen analyysi hyödyntää painetta kontrolloivaa röntgenfotoelektronispektroskopiaa (APXPS) pinnan pelkistysmekanismien tutkimiseen sekä termogravimetristä analyysia (TGA) kineettisten parametrien arviointiin suuremmassa mittakaavassa.
Tutkittaessa pinnan pelkistymistä vedyllä DRI-pelletti saavutti korkeamman metallisaatioasteen verrattuna BF-pellettiin, mikä johtui sen suuremmasta huokoisuudesta. Metallista rautaa ei muodostunut DRI-pelletissä, kun pelkistyskaasuun vedyn lisäksi lisättiin hiilimonoksidia. Kuitenkin BF-pelletti saavutti korkeamman metallisaatioasteen (20 %), kun pelkistyskaasujen suhde oli 50:50. Pelkistyneen raudan uudelleenhapettumista wüstiitiksi ja magnetiitiksi havaittiin tapahtuvan, kun H₂O- ja CO₂-osapaineet kasvoivat pelletin pinnalla.
Tutkittaessa vesihöyryn vaikutusta pelletin vetypelkistyksen aikana havaittiin, että vaikka täydellinen pelkistyminen on termodynaamisesti mahdollista vesihöyrypitoisuuden ollessa 30 %, wüstiitin pelkistyminen raudaksi ei tapahdu edes korkeissa lämpötiloissa kineettisten esteiden takia. Vesihöyrypitoisuuden ollessa 20 % pelkistymiseen vaikutti myös käytetty pelkistyslämpötila. Vaikka 10 prosentin vesihöyrypitoisuus hidasti pelkistysnopeutta, se ei vaikuttanut pelkistysasteeseen
Metal Oxide Gas Sensor Electronic Interfaces
No full textIn this chapter, we introduce Metal-Oxide (MOX) based semiconductor gas sensors as good candidates for realizing a gas sensing system due to their variety of advantages such as low cost, long life time, high sensitivity, small size, simplicity of operation, flexibility in production, and compatibility with the standard CMOS process.
A review of MOX gas sensors (commercial and noncommercial) is presented to draw the main requirements for the electronic interface circuit design.
The chapter presents a review of the state‐of‐the‐art for possible circuit interfaces provided in literature.
Electronic interface circuits based on time/frequency are preferable when converting wide resistance range with high linearity (low linearity error) without any need of calibration since the output periodic waveform can be easily converted to digital domain.
A detailed explanation for each building block constituting R‐to‐T architecture is provided highlighting the main requirements to achieve high linearity and wide dynamic range (DR)
Preface to 'Advanced neurotechnologies: Translating innovation for health and well-being'
No full textTowards flexible magnetoelectronics for robotic applications
No full textThis paper presents the technological advancements in the field of flexible magnetic sensors for robotics applications. Various magnetic devices (e.g. Hall, GMR, AMR and TMR) have been studied and their suitability for flexible application has been presented. Further, the system level integration of magnetic sensors in robotics is briefly discussed. With rapid development in flexible electronics, a robot with multi-functional conformable electronic skin will be possible in the foreseeable future. This will also open new avenues for a wide range of other applications including wearable electronics and interactive electronic-skin for robots and prosthesis
Agricultural Academy
No full textAbstract HEIDARI, H., 2015. Effect of defoliation based on leaf position on maize yield, yield components and produced seed germination. Bulg. J. Agric. Sci., Defoliation can affect maize seed yield. In order to determine the effect of defoliation treatments on maize yield, yield components and produced seed germination traits, a field and a laboratory experiments were conducted in 2012. The field experiment included six defoliation treatments (D1= control, no leaf removal, D2 = defoliating tassel leaf, D3 = defoliating ear leaf, D4 = defoliating leaves at the top of the ear, D5 = defoliating leaves under ear, D6 = defoliating all leaves). Germination traits of seed produced from maternal plant were tested at the laboratory experiment. Results showed that complete defoliation severely reduced seed yield, row number per ear, seed number per ear, cob length, cob weight and ear weight (P < 5%). Defoliation treatments had minor effect on produced seed germination traits
Wearable Electronics for Neurological Applications: A Review of Undergraduate Engineering Programmes
No full textNeuroscientists accept that we are indeed faced with an overwhelming challenge in understanding how the brain works. A better understanding of the brain will ultimately enable us to appreciate how well our students have grasped their learning materials. It will also enable us to diagnose and treat neurological disorders more effectively. Designing and developing the next generation of wearable devices is an important steppingstone towards this endeavor. Consequently, interdisciplinary efforts are required in co-creating educational materials that enable future neuro-engineers to develop these new devices. The aim of this article is to present a review of current undergraduate programmes that deal with this issue. Moreover, we provide recommendations for how new programmes in this field can be organized and delivered to ensure effective benefit for transnational students
Avian Influenza virus serological study among poultry workers in Iran
No full textObjective: Since the mid-1990s, H9N2 subtype influenza A viruses have caused infections in the poultry population
around the globe, including several countries in Asia, Europe, North Africa and America. H9N2 influenza
viruses are currently circulating in the Middle and Far East, as well as in European poultry, and the infection
seems to be endemic in most developing countries.
A significant proportion of recent H9N2 isolates contains the L-226 mutation in their hemagglutinin (HA) receptor-
binding site and shows preferential binding to analogs of receptors with α2,6-linked sialic acid (SA), which
are traits typical of human viruses. Thus, these avian viruses might possess one of the key elements for infection
in humans. The H9N2 virus was isolated for the first time from humans in Hong Kong in 1999 and until now
different human cases of AI H9N2 have been reported in different countries. The wide circulation of H9N2 viruses
throughout Europe and Asia, along with their ability to cause direct infection in mammals and humans, raises
public health concerns about their potential to become candidates for the next influenza pandemic (Li KS et
al.2003) in addition to the H5N1 virus. Since 1998 H9N2 AI has been reported in Iran (Nili H. 2003) and at present
is endemic in the poultry industry; despite the control measures, which include mass vaccination of poultry,
this virus has spread rapidly and is currently circulating in the country (Vasfi Marandi M.2013). This study
was carried out to reveal the potential exposure to H9N2 AI viruses among Iranian poultry workers.
Methods: A total of 200 subjects took part in this study, including 100 poultry workers and 100 healthy residents.
Serum samples were collected and tested for the presence of antibodies against two different H9N2 avian
influenza viruses by haemagglutination inhibition (HI) and microneutralization (MN) assays, the analyses were
repeated at least three times. Two Iranian H9N2 strains were isolated in 1998 and 2008, which showed different
phylogenetic and important molecular differences at aa 226 (Q/L) (H3 numbering),
(A/chicken/Iran/12VIR/9630/1998)/Q, (A/chicken/Iran/10VIR/854-5/2008)/L. The viruses were replicated in SPF
chicken eggs and used in the serological study as antigens. In addition, all samples were tested for the presence
of seasonal H3N2, H1N1 2009 pandemic human influenza viruses to verify the presence of cross positivity
with the previously listed influenza viruses.
Results: Serological results showed that 16% of the exposed poultry workers were positive for the
A/chicken/Iran/10VIR/854-5/2008 virus in MN test and 12.33% in HI test using the titer > 40 as positive cut-off
value. Only 2% of the exposed staff was positive for the A/chicken/Iran/12VIR/9630/1998 virus. Seroprevalence
of control subjects for both H9N2 strains was very low in both tests (1-2%).
Conclusion: The results of this study have demonstrated that exposure to avian H9N2 viruses had occurred
among poultry workers in the Shiraz region – Iran, with a higher percentage than that recorded in the control
population of the same geographic area. Continuous surveillance programmes should be implemented to monitor
the presence of avian influenza infections in humans and to evaluate their potential threat to public health
and poultry workers
Thermo-Mechanical Buckling and Non-Linear Free Oscillation of Functionally Graded Fiber-Reinforced Composite Laminated (FG-FRCL) Beams
No full textWe investigated the thermal buckling temperature and nonlinear free vibration of functionally graded fiber-reinforced composite laminated (FG-FRCL) beams. The governing nonlinear partial differential equations were derived from the Euler–Bernoulli beam theory, accounting for the von Kármán geometrical nonlinearity. Such equations were then reduced to a single equation by neglecting the axial inertia. Thus, the Galerkin method was applied to discretize the governing nonlinear partial differential equation in the form of a nonlinear ordinary differential equation, which was then solved analytically according to the He’s variational method. Three different boundary conditions were selected, namely simply, clamped and clamped-free supports. We also investigated the effect of power-index, lay-ups, and uniform temperature rise on the nonlinear natural frequency, phase trajectory and thermal buckling of FG-FRCL beams. The results showed that FG-FRCL beams featured the highest fundamental frequency, whereas composite laminated beams were characterized by the lowest fundamental frequency. Such nonlinear frequencies increase for an increased power index and a decreased temperature. Finally, it was found that FG-FRCL beams with [0/0/0] lay-ups featured the highest nonlinear natural frequency and the highest thermal buckling temperature, followed by [0/90/0] and [90/0/90] lay-ups, while a [90/90/90] lay-up featured the lowest nonlinear natural frequency and critical buckling temperature
Modelling of POSFET Devices for Large Area Touch Sensing Applications
No full textDevelopment of touch sensing systems for electronic skin is one the emerging application for large area electronics. The ongoing related research in BEST group includes Piezoelectric Oxide
Semiconductor Field Effect Transistor (POSFET) devices based touch sensors. These devices, use piezoelectric polymer P(VDF-TrFE) to modulate the charge carriers in the channel and
hence convert contact/touch into current or voltage signal. Here we present a novel model for this type of device and show how the piezoelectric materials modulates the charge in the channel region of underlying transisto
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