Room temperature ageing of Al–Ni–RE (RE = La, Gd, Er) metallic glasses

The effect of long-term ageing of Al–TM–RE (TM = Ni, Ag, Cu; RE = rare earth) amorphous alloys under ambient conditions, and at a slightly elevated temperature (100 °C), has been studied. The phase evolution and devitrification kinetics were studied using differential scanning calorimetry, X-ray diffraction and transmission electron microscopy techniques. Partial crystallization was observed in Al89Ni6La5, Al87Ni6La7, Al87Ni5(Ag/Cu)1La7 alloys after several years under ambient conditions (20–50 °C), and in Al88Ni4La8, Al88Ni4Gd2Er6 and Al88Ni4Er8 alloys following a 90 h anneal at 100 °C

Association of ABO blood group with severe falciparum malaria in adults: case control study and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Erythrocyte-associated antigenic polymorphisms or their absence have perhaps evolved in the human population to protect against malarial infection. Studies in various populations consistently demonstrate that blood group 'O' confers resistance against severe falciparum infection. In India, Odisha state has one of the highest incidences of <it>Plasmodium falciparum </it>infection and contributes to the highest number of deaths by falciparum malaria. This study aims to evaluate the relationship between ABO blood group and severe malaria in an adult population at the tertiary care centre in Odisha.</p> <p>Methods</p> <p>A total of 353 <it>P. falciparum </it>infected subjects and 174 healthy controls were screened for ABO blood group. Falciparum-infected individuals were categorized as severe malaria and uncomplicated malaria. Severe malaria was further clinically phenotyped into cerebral malaria, non-cerebral severe malaria and multi-organ dysfunction. A meta-analysis was performed to assess the role of ABO blood group in severe malaria.</p> <p>Results</p> <p>Frequency of blood group 'B' was significantly higher in patients with severe malaria compared to the uncomplicated cases (P < 0.0001; OR = 4.09) and healthy controls (P < 0.0001; OR = 2.79). Irrespective of the level of clinical severity, blood group 'B' was significantly associated with cerebral malaria (P < 0.0001; OR = 5.95), multi-organ dysfunction (P < 0.0001; OR = 4.81) and non-cerebral severe malaria patients (P = 0.001; OR = 3.02) compared to the uncomplicated category. Prevalence of 'O' group in uncomplicated malaria (P < 0.0001; OR = 2.81) and healthy controls (P = 0.0003; OR = 2.16) was significantly high compared to severe malaria. Meta-analysis of previous studies, including the current one, highlighted the protective nature of blood group 'O' to severe malaria (P = 0.01). On the other hand, carriers of blood group 'A' (P = 0.04) and 'AB' (P = 0.04) were susceptible to malaria severity.</p> <p>Conclusions</p> <p>Results of the current study indicate that blood group 'O' is associated with reduced and 'B' blood group with increased risk of development of severe malaria in Odisha, India. Meta-analysis also supports the protective nature of blood group 'O' from severe falciparum infection.</p

Glass transition and crystallization of Al–Ni–La based metallic glasses studied by temperature modulated DSC

Crystallization behavior and glass transition phenomenon of Al89Ni6La5, Al87Ni6La7 and Al87Ni5La7M1 (M = Ag, Cu) metallic glasses have been studied by temperature modulated differential scanning calorimetry (TMDSC). A clear glass transition of these glasses, which could not be detected in conventional differential scanning calorimetry (DSC), even at higher heating rates, was observed through TMDSC measurements. All these glasses undergo two-stages of crystallization on heating. The precipitation and growth of fcc-Al in Al89Ni6La5 and bcc-metastable phase in other alloys are responsible for the first stage of crystallization. The glass transition phenomenon in these alloys except Al87Ni6La7, could not be detected in DSC because the signals are overlapped with the relatively large heat release from the primary crystallization. This was confirmed from the TMDSC measurements. These measurements were necessary for the development of new nanocrystalline/amorphous composite materials

Environmental impact of spent lithium-ion batteries and green recycling perspectives by organic acids - A review

The huge usage of rechargeable batteries in electronics has added to a recurrent problem worldwide in generating tonnage of spent lithium-ion batteries (LIBs). The inadequacy of the resources of the depleting critical metals has also been described in vogue. The environmental assessment of the life cycle of the LIBs has been elucidated vis-a-vis the effects of raw material supply, transportation, and recycling. Based on the available work for recycling technologies, this review also attempts to elicit the various methods practiced in discharging/dismantling, classification, and separation of components followed by metal recovery. The authors have reviewed the major developments in the area of recycling of cathode material by using various acids for extraction of metals from spent LIBs, compared the merits and demerits of acids used and presented a comprehensive outlook to the processes formulated vis-a-vis imperative need for using green techniques. The necessity for benign recycling methods is stressed upon to alleviate the need for high temperature and oxidative acid leaching conditions. The various green lixiviants (organic acids) attempted to extract metals from spent LIBs have been discussed in detail with respect to the mechanism, efficacies as well as the various factors (selectivity, cost, etc.) that govern the use of organic acids in battery recycling. It was ascertained that the GHG emissions to extract Co using organic acids stand 1/8 of that using an inorganic acid leaching process. Efforts need to be envisaged in separating the leached metals from these lixiviants ensuring economics and environmental benefits

Production of perfect sinter-Need for blast furnaces

This paper presents a number of factors influencing Sinter Quality like particle grain size which relates the FeO content in sinter, the CaO/SiO ratio of 2 the sinter raw mix, chemical composition of the raw materials, especially with respect to the gangue content (SiO , MgO, Al O ), interstitial water. It relates 2 2 3 sinter-Plant Operational Parameters on Sinter Quality by focusing on effect of homogeneous sinter raw mix of high permeability on fuel consumption for the sintering process, increased sintering time on the mean diameter of the sinter product, effect of the suction pressure on productivity of the sinter plant, the ideal positioning of the burn through point. The study depicts the influence of Sinter- Plant Equipment on Sinter Quality and Quantity, are also discussed addition of burnt lime in sinter-mix oil, sintering process of iron ore fines. The result found have been encouraging with significant increase in productivity, reduces solid fuel rate, lower consumption of fossil fuel and better strength along with higher reducibility

Reclaiming iron from solid wastes via Romelt process

The ROMELT[1] process of iron making uses non coking coal and iron bearing materials such as metallurgical wastes, including finely dispersed ecologically dangerous dusts and sludge as chiefraw materials, that proves promising for the disposal and reuse of the latter generated in both ferrous as well as non ferrous industries. Besides, non coking coal cuts out the requirement of an energy intensive and hazardous coking process. Although its capacity isn't comparable to that of the blast furnaces, this single stage process can be established virtually anywhere and provide an exceptionally high grade of hot metal for steel making purposes. In the present scenario of global recession and environmental consciousness, the commercialisation of this process can ensure bothcheaper and a better quality iron, along with fewer casualties to nature. A review of the Romelt process has been carried out and its comparison with the other existing alternative processes of iron making[10] (such as Corex process, Hismelt process, etc.) has been done. In the end, suggestions regarding popularising this technology, highlighting its applicability to the Indian conditions have been made

Kinetic aspects of the nanocrystallization and evolution of microhardness in Al92-XNi8LaX amorphous alloys

Marginal glass forming Al-based alloys have attracted considerable attention due to the occurrence of a primary crystallization reaction that yields a microstructure consisting of uniformly dispersed Al-nanocrystals embedded in an amorphous matrix. Rapidly solidified Al-alloys ribbons containing 8 at.% Ni and 4-6 at.% La were prepared by single roller melt-spinning technique. As-melt-spun and annealed ribbons were investigated by means of differential scanning calorimetry ( DSC), X-ray diffractometry ( XRD) and hardness measurements. XRD studies revealed that ribbons are fully amorphous in the as-melt-spun state. DSC studies showed that crystallization proceeds in two or three stages that are sensitively influenced by La content. Crystallizations kinetics were analysed by Kissinger and Johnson-Mehl-Avrami approaches. Microhardness of all the ribbons was examined at different temperatures and correlated with the corresponding structural evolution

Studies on crystallization behaviour and mechanical properties of Al-Ni-La metallic glasses

Alloy ingots with nominal composition, Al92−x Ni8La x (x = 4 to 6) and Al94−x Ni6La x (x = 6, 7), were prepared by induction melting in a purified Ar atmosphere. Each ingot was inductively re-melted and rapidly solidified ribbons were obtained by ejecting the melt onto a rotating copper wheel in an argon atmosphere. The crystallization behaviour of melt-spun amorphous ribbon was investigated by means of differential scanning calorimetry (DSC), X-ray diffractometry and transmission electron microscopy. DSC showed that Al86Ni8La6 alloy undergoes a three-stage and rest of the alloys undergo a two-stage crystallization process upon heating. The phases responsible for each stage of crystallization were identified. During the first crystallization stage fcc-Al precipitates for low La-containing alloys and for higher La-containing alloys a bcc metastable phase precipitates. The second crystallization stage is due to formation of intermetallic compounds along with fcc-Al. Microhardness of all the ribbons was examined at different temperatures and correlated with structural evolutions. Precipitation strengthening of nano-size fcc-Al is responsible for maximum hardness in these annealed alloys

Recycling of Precious Metal Gold from Waste Electrical and Electronic Equipments (WEEE): A review

Gold finds a wide range of application in electronic devices i.e. in mobile phone PCBs, coated plates, connectors etc. This is because of its high conductivity, ability to carry low ampere current, high sensitivity and resistance to corrosion. Due to the increasing demand of electronic devices conventional reserves of gold are depleting. At the same time life of electronic goods is decreasing because of rapid changes in device features and abilities. This produces a large amount of obsolete electronic gadgets which gradually results into a large amount of electronic waste. Even during production of electronic products, steps involved generate waste water containing gold which can be recycled. In order to meet the increasing demands and conserve resources, it is necessary to recycle the e-waste generated. Gold recovery is also necessary because of its high market value and vast application in different fields such as jewelry, coinage, medical appliances etc. Recovery of gold from e-waste has gained attention because of its concentration in e-waste which is around 100 times more than that is found in gold ores. The present paper gives an idea of the various hydrometallurgical processes such as cementation, adsorption, solvent extraction etc used in the recovery of gold from electronic scrap. The paper also highlights the use of different types of leachants such as Cyanide, Thiourea, Thiosulfate etc. for the recovery of gold. Chemical reactions and the process parameters viz. pH, temperature, concentration of leachant, pulp density, stirring speed etc. involved in different processes are also reported. Based on the review made, some flow sheet and recommendations have been proposed for effective and feasible recovery /recycling of gold from e-waste