IR@CECRI
Not a member yet
2644 research outputs found
Sort by
Poly (vinyl alcohol) hydrogel membrane as electrolyte for direct borohydride fuel cells
No full textA direct borohydride fuel cell (DBFC) employing a poly (vinyl alcohol) hydrogel membrane
electrolyte (PHME) is reported. The DBFC employs an AB5 Misch metal alloy as anode and a goldplated
stainless steel mesh as cathode in conjunction with aqueous alkaline solution of sodium borohydride
as fuel and aqueous acidified solution of hydrogen peroxide as oxidant. Room temperature performances
of the PHME-based DBFC in respect of peak power outputs; ex-situ cross-over of oxidant,
fuel, anolyte and catholyte across the membrane electrolytes; utilization efficiencies of fuel and oxidant,
as also cell performance durability are compared with a similar DBFC employing a Nafion®-117 membrane
electrolyte (NME). Peak power densities of ~30 and ~40 mW cm–2 are observed for the DBFCs
with PHME and NME, respectively. The crossover of NaBH4 across both the membranes has been found
to be very low. The utilization efficiencies of NaBH4 and H2O2 are found to be ~24 and ~59%, respectively
for the PHME-based DBFC; ~18 and ~62%, respectively for the NME-based DBFC. The PHME
and NME–based DBFCs exhibit operational cell potentials of ~1⋅2 and ~1⋅4 V, respectively at a load current
density of 10 mA cm–2 for ~100 h
Observation of self-regulating response in LixMyMn2-yO4 (M = Mn, Ni): A study using density functional theory
No full textDensity functional theory is used to understand the response of the transition metal–oxygen octahedra
in LixMn2O4 and LixNi0.5Mn1.5O4 to lithium intercalation and de-intercalation. Electronic structure
computations on these compounds for x ¼ 0, 0.5 and 1 indicate that the 3d DOS of Mn is almost
unaffected to variations in x. On the other hand, the oxygen 2p-DOS and to a lesser extent Ni 3d DOS are
found to be sensitive to perturbation. The observations are explained on the grounds of self-regulating
response, characteristic of systems having localized d states that communicate with a covalent
manifold
Augmentation of biodegradability of pulp and paper industry wastewater by electrochemical pre-treatment and optimization by RSM
No full textBiological treatment of pulp and paper industry wastewater is made effective by giving a simple electrochemical
pre-treatment. Biodegradability index is found to be improved from 0.11 to 0.46 by a short
(6.9 min) treatment in mild conditions (current density: 112.9Am−2, pH 7.3). The optimal operating point
for maximum biodegradability has been found out using response surface methodology (RSM). It is also
noticed that there exists an optimal operating point for maximum biodegradability. The specific energy
consumption and current efficiency figures at the optimal condition are also promising. Moreover there
is considerable reduction in the pollutant load (COD removal: 55% and color removal: 87%). Performance
of the process at this operating point has been validated by running biological treatment. Considerable
reduction in the requirement of biological reactor volume can be expected by giving such a simple
electrochemical pre-treatment
Embeddable corrosion rate-measuring sensor for assessing the corrosion risk of steel in concrete structures
No full textNew and rehabilitated concrete structures need assessment of corrosion rate (CR) of rebars more
precisely to ensure efficiency of protection against corrosion. For assessing the corrosion status, different
sensors have been developed to reduce the risk of undetected corrosion problems. An embeddable
CR-measuring sensor is embedded either closer to the rod during the construction of a new structure
or in drilled holes in old structures so as to generate reliable data. In the present paper, the accuracy in
predicting the corrosion current (Icorr) by embeddable sensor was assessed by comparing with other
conventional electrode arrangements. Icorr was assessed under passive and active conditions of rebar.
The presence of a cross bar and the effect of cover on Icorr were also studied. Using linear polarization
resistance (LPR) technique and electrochemical impedance spectroscopic (EIS) technique, the CR was
determined and compared with the weight-loss method. Results concluded that by using electrochemical
impedance technique, developed embeddable sensor is able to predict the CR very close to the CR
determined from gravimetric method. The deviation from an ideal linear curve and the higher interfacial
capacitance of steel in concrete caused the LPR method to underestimate the CR of rebar. The presence of
the cross bar increases the Icorr of the main bar by 4 times in a passive state of the rebar and it has no effect
if the rebar is in an active state. The embedded sensor, though having smaller counter electrode (CE),
polarizes the rebar up to 2 times the length of CE under both active and passive states
Electrodeposition of zinc–nickel alloy by pulse plating using non-cyanide bath
No full textIn this study, zinc–nickel electrodeposition was carried out in a sulphamate bath at pH 3–4 by
pulse plating and the deposits obtained were characterised by measuring microhardness,
surface roughness and by employing SEM, XRD, AFM techniques. The corrosion behaviour of the
deposits was evaluated by potentiodynamic polarisation. The deposits obtained by pulse plating
have an increased Ni content, thought to be responsible for an improved corrosion resistance
Morphology and texture of pulse plated zinc–cobalt alloy
No full textPulse electrodeposition was used to produce zinc–cobalt (Zn–Co) alloy deposits from an alkaline noncyanide
electrolyte with and without additives. The influence of additives’ concentration and pulse
parameters, such as ON-time (TON), OFF-time (TOFF), and pulse peak current density (IP) on the surface
morphology, grain size, composition and crystal orientation were investigated using scanning electron
microscope (SEM), atomic forced microscope (AFM), energy dispersive X-ray (EDX), X-ray fluorescence
(XRF),X-ray diffraction (XRD), respectively.At constant TOFF and IP, cobalt content in the deposits decreases
with TON and cluster size increases. Increase in TOFF at constant TON and IP, decreases the cluster growth
with increase in cobalt content. The same trend was observed with increasing IP (without additives) at
constant TON and TOFF. The presence of additives at 7Adm−2 drastically decreases the cobalt content in
the deposits from 2.5 to 0.7 wt.%. Co and the preferred crystallographic orientation was [10.1] at 69.1% as
confirmed by XRD
Studies on the evaluation of the performance of organic coatings used for the prevention of corrosion of steel rebars in concrete structures
No full textCorrosion of steel rebars in reinforced concrete constructions, particularly those located in marine environments
and industrially polluted areas is one of the major problems baffling the construction industry
all over theworld including India. A suitable protective coating to rebar is found to improve the durability
of such structures under aggressive exposures. The performance of a fewpolymeric coatings based on different
resins such as acrylic polyol-aromatic isocyanate, polyester polyol-aromatic isocyanate, acrylic resin
and epoxy–silicone–polyamide containing ordinary Portland cement or flyash as extenders and titanium
dioxide and zinc phosphate as main pigments on rebar in concrete has been evaluated using mechanical
strength tests and accelerated corrosion tests. It is observed that, of the 16 coating formulations, four have
been found to perform well as effective and durable coatings
An eco-friendly electrolytic process for the production of aluminium
No full textThe present invention relates to an eco-friendly electrolytic process for the production of aluminum from fused salts such as alumina dissolved in cryolite melt. This eco-friendly electrolytic process for the production of aluminum involves single step electrolysis of alumina to give aluminum metal and pure oxygen gas, which can be concentrated and sold as a valuable co-product along with the primary product, that is aluminum metal. Presently aluminum is produced using consumable carbon anodes. Hitherto during the production of aluminum from alumina, green house gases such as carbon dioxide and carbon monoxide are evolved. The present invention mitigates this, by the use of cermet anode at which only pure oxygen is evolved. Thus the process is eco-friendly not only by the elimination of CO2 and CO during the electrolysis but also enhances the environmental hygiene by the addition of pure oxygen gas. The electrolysis can be carried out in closed electrolysers to give higher space time yield. The process of the invention enables the production of aluminum metal by a green process. The purity of the product is of the order of 99.4% at an average current efficiency of 85% and an energy consumption of 13.4 Kwh per Kg of aluminum
Impact of Ammonia Producing Bacillus sp. on Corrosion of Cupronickel alloy 90:10
No full textThe objectives of the present investigation were to characterize ammonia-producing bacteria (Bacillus sp.)
and study its impact on biodeterioration of cupronickel alloy 90:10. in a nitrogen free environment. It is
well known that iron sulphate and molybdenum are good inhibitors when used in a cooling water system.
The interactions between inhibitor and ammonia producing bacteria on the corrosion of cupronickel 90:10
were studied. The predominated ammonia producing bacteria Bacillus sp. (AG1-EU202683; AG2-EU202684;
AG3-EU202685 and AG4-EU202686) were identified by 16S rRNA gene sequencing from the biofilm. These bacteria fixed with atmospheric nitrogen for their cell protein synthesis and converted into ammonia. Ammonia enhanced pH and ammonical solution were formed in the presence of Bacillus spp. which acted as an etchant. The presence of some anodic spots in the presence of bacteria was affected by ammonia and then underwent pitting corrosion. The present study reveals that Bacillus spp. encourage intergranular attack without any stress in the cooling water system
Corrosion protection of galvanized iron by polyaniline containing wash primer coating
No full textWash primer treatment of galvanized iron (GI) structure is widely used before painting in order to improve
adhesion. Traditional wash primer contains zinc tetroxy chromate. Due to hazardous nature of chromate,
alternate compounds for chromate replacements have been identified. In recent years polyaniline containing
coating has been found to protect GI. In this study, a wash primer based on polyaniline has been
formulated and its corrosion protection ability of GI has been compared with that of traditional chromate
based wash primer by salt spray and EIS test. It has been found that the polyaniline based wash primer
is able to protect GI and its corrosion protection performance is similar to chromate based wash primer
coating