Novel method for refinement of retained austenite in micro/nano-structured bainitic steels

A comparative study was conducted to assess the effects of two different heat treatments on the amount and morphology of the retained austenite in a micro/nano-structured bainitic steel. The heat treatments used in this work were two-stage bainitic transformation and bainitic-partitioning transformation. Both methods resulted in the generation of a multi-phase microstructure containing nanoscale bainitic ferrite, and/or fresh martensitic phases and much finer retained austenite. Both heat treatments were verified to be effective in refining the retained austenite in micro/nano-structured bainite and increasing the hardness. However, the bainitic transformation followed by partitioning cycle was proved to be a more viable approach than the two-stage bainitic transformation due to much shorter processing time, i.e. ∼2 h compared to ∼4 day, respectively

Ethanolic extract of anise (Pimpinella anisum L.) attenuates morphine physical dependence in mice

Introduction: Previous studies revealed that anise (Pimpinella anisum L.) has several pharmacological effects including analgesic, antidepressant, anxiolytic, anti-inflammatory and antispasmodic activities. This study aimed to evaluate its effect on morphine physical dependence in mice. Methods: In this experimental study, 40 male NMRI mice (25-30 g) were randomly divided into 5 groups of 8. Control group received morphine and normal saline (10 mL/kg, i.p.) and other groups received diazepam (5 mg/kg) plus one of three doses of P. anisum (50,100 or 200 mg/kg, i.p.). Dependence was induced by administration of increasing doses (50-75 mg/kg, i.p.) of morphine. A time of 30 minutes after naloxone injection was considered for the critical period of the withdrawal syndrome. The number of jumps and scores of 0 to 3 were given for incidences of wet dog shakes, teeth chattering, climbing, writing, diarrhea, grooming, and rearing during a 30-minute period. Results: All doses of P. anisum (P<0.01) reduced the number of jumps. Additionally, all doses of the extract reduced the behaviors of grooming (P<0.05, P<0.01 and P<0.01, respectively) and writhing (P<0.05, P<0.001and P<0.001, respectively). None doses of the extract could reduce diarrhea (P>0.05). Climbing, rearing and wet dog shakes reduced only by the high dose of the extract (P<0.05). Teeth chattering reduced by 100 and 200 mg/kg of the extract (P<0.05). Conclusion: These results obviously show that P. anisum ethanolic extract is effective in suppression of morphine physical dependence and further studies are needed to find out the responsible constituents and also the exact mechanisms of actions

Gallium-assisted diffusion bonding of stainless steel to titanium; microstructural evolution and bond strength

Strong joints between stainless steel 304L and pure titanium (grade-2) were made using the novel method of “gallium-assisted diffusion bonding”. The microstructural evolution and interfacial reactions were investigated in detail. The possible mechanisms of phase changes at the joint interface when bonding with and without a nickel interlayer were identified. Layers of FeTi and (Fe,Cr)2Ti intermetallic compounds were found at the reaction zone in the case of direct bonding, whereas (Fe,Ni)Ti and Fe2Ti phases were identified in the reaction zone of the samples bonded using nickel interlayers. A layer of αFe was observed on the steel side of the reaction zone in both the cases, probably due to the enrichment of Cr at the interface. The diffusion of gallium led to formation of a layer of αTi, while the diffusion of Fe and Ni assisted in the formation of a duplex (α+β)Ti phase in the inter-diffusion zone. The joints fractured along the intermetallic layers at the interface, during tensile testing, with limited ductility. The maximum tensile strengths of the bonded samples were 280 and 313 MPa with and without nickel interlayer, respectively. The latter equals 92% of the tensile strength of the pure grade-2 titanium used in this work (i.e. 340 MPa)

Modelling and design of new stainless-steel welding alloys suitable for low-deformation repairs and restoration processes

The plasticity associated with low-temperature martensitic transformation can be exploited to reduce the stresses developed due to thermal contraction of the weldments. The key feature of stress-mitigating welding alloys is their transformation from austenite to martensite at low temperatures e.g. ideally close to ambient temperature. Thermodynamics databases (MTDATA and SGTE) were used to model and design new welding alloys with low martensitic transformation temperatures (Ms) around 200 °C. The modelling, conducted in this work, was based on this assumption that martensitic transformation starts at a certain temperature when the free-energy change for austenite to transform to ferrite reaches a critical value. Since martensitic transformation is a diffusion-less process, the change in free-energy vs. temperature was calculated for the austenite and ferrite phases with the same composition. Three prototype welding alloys, CamAlloys 4 & 5 and OpenAlloy 1, were successfully designed and made in the University of Cambridge (UK) and the Open University (UK). The design of these alloys was purely based on thermodynamics equations. Comprehensive characterisation, examinations and mechanical tests showed this family of alloys could substantially reduce contraction-induced deformations in stainless steel weldments. One of the applications of these alloys is in the repair and restoration of damaged stainless-steel components

Molecular and parasitological study of cutaneous leishmaniasis in Bushehr province, southwest of the Islamic Republic of Iran: a cross-sectional study during 2009–2012

Cutaneous leishmaniasis (CL) is one of the most important parasitic disease in Iran. CL is distributed among more than half of 31 provinces of Iran. Studies on epidemiological aspects of the disease and Leishmania species identification among infected humans are necessary for providing a comprehensive prevention and control program thus; this descriptive cross-sectional study was conducted on all CL suspected patients who referred to Health Centers of Bushehr province from 2009 to 2012. Physical examinations were carried out in suspected individuals and CL cases were confirmed by microscopical examinations. Prepared slides from suspicious cases of CL were fixed with absolute methanol and stained by Giemsa 10 %. All the Giemsa-stained slides examined under a light microscope with high magnification (1,0009) and classified them based on grading of Leishmania parasites. DNA from each slide was extracted, separately. The ribosomal internal transcribed spacer 1 was amplified with specific primers and PCR products were digested by restrict enzymes (HaeIII), run them in 3 % gel agarose for electrophoresis and visualized on a UV transilluminator after staining with ethidium bromide. SPSS version 21 was used for data analyses. A total of 726 suspected CL cases were referred to Health Centers of Bushehr province from 2009 to 2012 and samples were only prepared from 188 of the patients whereas 43 (5.9 %) of them were microscopy positive. The most frequent of CL was observed in November (14 %) and December (12 %). The most distribution of CL lesions were observed on hands (32 %), feet (26 %), and face (21 %), respectively. The highest frequency of CL was observed in 1–9 years old (30 %). Altogether, 50 % of the patients showed one skin lesion and 2–10 skin lesions were occurred in the remained CL patients. Totally, 27 out of 43 (63 %) of the Giemsa stained slides were positive by PCR–RFLP assay because all the PCR–RFLP negative slides were prepared 3–4 years ago and kept without cover slip, and also observed scarce amastigotes during microscopy observations. Leishmania species were identified in 21 desirable slides which 14 of them were L. major and 7 of the remained isolates were identified L. tropica using PCR–RFLP

Cutaneous Leishmaniasis in Bam: A Comparative Evaluation of Pre- and Post- Earthquake Years (1999-2008)

Background: The recent devastating earthquake of December 26 in Bam, 2003 created various risk factors; caused a sharp increase in incidence of anthroponotic cutaneous leishmaniasis (ACL) cases and reached to an epidemic proportion. The objective of this study was to evaluate the status of ACL cases five years before the earthquake compared to the cases occurred five years after the earthquake (1999-2008). Methods: Status of disease was assessed retrospectively for the five years before the earthquake and prospectively for the five years after the earthquake. Identification was confirmed by smear and polymerase chain reaction (PCR). Results: The mean annual incidence of ACL for the period from 1999 to 2003 was 1.9 per 1000 comparing to post earthquake period, which was 7.6 per 1000. Most of the infection was in individuals of <20 years, more frequently in females before the earthquake, whilst in contrast, there was a progressive rise in the number of cases, significantly in male individuals of >20 years (P< 0.0001) in post earthquake era. The anatomical distribution of lesions considerably changed during the two periods. Most of the cases were limited to three zones within the city prior to the earthquake, whereas it was spread throughout different zones after the earthquake. PCR indicated that the CL was due to Leishmania tropica in the city. Conclusion: The results strongly suggest that in natural disasters such as earthquakes various precipitating factors in favor of disease will be created, which in turn provide a suitable condition for propagation of the vector and the transmission of the parasite

Effect of Silicon Content on Carbide Precipitation and Low-Temperature Toughness of Pressure Vessel Steels

Cr – Mn – Mo – Ni pressure vessel steels containing 0.54 and 1.55% Si are studied. Metallographic and fractographic analyses of the steels after tempering at 650 and 700°C are performed. The impact toughness at – 30°C and the hardness of the steels are determined. The mass fraction of the carbide phase in the steels is computed with the help of the J-MatPro 4.0 software

Growth and nutrient removal capacity of Chlorella vulgaris microalgae in high ammonia media

Wastewater treatment is essential to remove toxic particulates before it is discharged to the surrounding environment. Recently, algal-based systems have been widely used for wastewater treatment. However, there is a lack of studies on algal growth’s feasibility in high ammonia media. In this research, the growth of Chlorella Vulgaris microalgae in high ammonia media was investigated. In the first stage, 200, 400, 600, and 800 mg/l of ammonia (NH4) levels were applied. The optimal growth and nutrient removal were achieved with 600 mg/l ammonia. Biomass concentration of 1268 mg/l and ammonia removal of 348 mg/l was obtained. Algae had low growth in a high-ammonia medium (800 mg/l). In the second stage, the buffering system of CO2/ NaHCO3 was applied. Different carbon dioxide concentrations (2, 4, and 6%) and sodium bicarbonate (1, 1.5 and 2 g/l) were investigated. The best results (biomass concentration and ammonia removal of 1740 and 417.33 mg/l, respectively) were obtained with 4% CO2 and 1.5 gr/l NaHCO3. This study shows the feasibility of C. Vulgaris growth in harsh low-pH conditions and its optimal conditions to remove nutrients from wastewater.May 202