Arjun Dey

Black anodic coating (BAC) was fabricated on additively manufactured (AM) or 3D printed Al–10Si–Mg alloy for use in various spacecraft components, such as electronic housings, antenna feeds, wave guides, structural brackets, collimators, thermal radiators, etc. The surface morphology, near-surface elemental/electronic structure and chemical nature...

The Solar Ultraviolet Imaging Telescope (SUIT) is an instrument on the Aditya-L1 mission of the Indian Space Research Organization (ISRO) launched on 2 September 2023. SUIT continuously provides near-simultaneous full-disk and region-of-interest images of the Sun, slicing through the photosphere and chromosphere and covering a field of view up to 1...

Aditya-L1 is the first space-based solar observatory from India, which is studying the Sun and solar wind from the first Lagrangian point (L1) in a halo orbit. Among the seven payloads, four of them are remote sensing and three are in situ ones. The Plasma-Analyzer Package for Aditya (PAPA) is one among the in situ payloads for exploring the compos...

Nowadays, anodic coating on additively manufactured (AM) or 3D printed Al–10Si–Mg alloy are used for various components in spacecraft such as antenna feeds, wave guides, structural brackets, collimators, thermal radiators etc. In this study, artificial neural network (ANN) and power law-based models are developed from experimental nanoindentation d...

Crystalline vanadium oxide-titanium oxide (VO-TO) composite thin films of 197 nm are developed on quartz and silicon substrates by RF magnetron sputtering technique. A thorough structural investigation of deposited thin films is carried out by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and X-ray diff...

The present work reveals the variation of nanomechanical properties (nanohardness-H and modulus-E) of black anodic coating on additively manufactured Al–10Si–Mg alloy. The plan-section of the coating has mud-crack-like morphology with various nano/micro-pores, micro-channels, and irregularities. In contrast, the cross-section possesses a compact mo...

The air plasma spraying (APS) method is used for coating the pure alumina (PA) and composite of alumina–titania (AT) on 304 stainless steel substrates. For the composite coatings, in the alumina matrix, the percentage addition of titania was13 wt% (AT13) and 40 wt% (AT40). For all APS coatings, microstructures were studied using scanning electron m...

Understanding the mechanical response and failure of consolidated extra-terrestrial soils requires analyses of the interactions between propagating cracks the material’s inherent pore structure. In this work, we investigate the fracture behaviour of lunar soil simulant consolidated using microbially induced calcite precipitation (MICP). We develop...

Black appearance and flat absorber, i.e., high solar absorptance (αs) and high IR emittance (εir) surfaces, are essential for optical benches and optical mounts in astronomical and scientific payloads/spacecraft. Generally, these optical benches and optical mounts are fabricated by Ti6Al4V alloy due to their superior mechanical and thermal properti...

Understanding the mechanical response and failure of consolidated extra-terrestrial soils requires analyses of the interactions between propagating cracks the material's inherent pore structure. In this work, we investigate the fracture behaviour of lunar soil simulant consolidated using microbially induced calcite precipitation (MICP). We develop...

Black anodic coating (BAC) is developed on 3D printed or additively manufactured (AM) Al–10Si–Mg alloy by sulphuric acid based anodization technique at low (∼9 °C) temperature. The microstructural and surface properties of the coating are investigated by optical microscopy (OM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-r...

We demonstrate that Microbial Induced Calcite Precipitation (MICP) can be utilized for creation of consolidates of Martian Simulant Soil (MSS) and Lunar Simulant Soil (LSS) in the form of a ‘brick’. A urease producer bacterium, Sporosarcina pasteurii, was used to induce the MICP process for the both simulant soils. An admixture of guar gum as an or...

Copper oxide (CuO) nanostructures have gained significance due to their chemical and physical properties that find applications in sensing, electronics and minimizing solar background count in spaceborne plasma instruments. In this work, a wet-chemical route has been utilized to synthesize nanostructured CuO coating on aluminum alloy substrates. Th...

The present work explores the adaptive behavior of well-known ureolytic bacterial strain namely Sporosarcina pasteurii for microbial-induced calcite precipitation (MICP) under saline environment. MICP activity was observed up to 10% NaCl supplementation and confirmed by several characterization techniques viz. scanning electron microscopy (SEM), X-...

We demonstrate that Microbial Induced Calcite Precipitation (MICP) can be utilized for creation of consolidates of Martian Simulant Soil (MSS) and Lunar Simulant Soil (LSS) in the form of a 'brick'. A urease producer bacteria, Sporosarcina pasteurii, was used to induce the MICP process for the both simulant soils. An admixture of guar gum as an org...

We have fabricated VO2 nano-columns (NCs) on the aluminized quartz glass substrates using glancing angle deposition (GLAD) technique inside the electron beam (e-beam) evaporator chamber. An e-beam deposited TiO2 thin cap-layer has been introduced on the top of the VO2 NCs to protect VO2 phase which is usually unstable and turns to stable higher oxi...

Biological experiments on bacteria in extra-terrestrial environments have recently gained increased importance in the context of space exploration and the human space programme. Here, we demonstrate a modular self-contained device, based on the lab-on-a-chip (LoC) paradigm, for performing miniaturized biological experiments in microgravity or outer...

Amorphous vanadium pentoxide (major phase) thin films of various thicknesses were grown on the substrates that possessed low (aluminized quartz) and high (quartz) infrared (IR) emittance property utilizing radio frequency (RF) magnetron sputtering technique. Microstructural characterizations are carried out by several techniques such as noncontact...

We propose a facile and combined methodology to develop magnetron sputtered various metals and alloy (e.g. tungsten, tin and nichrome), and metal oxide (indium tin oxide) thin film-based micro-patterns deposited on flexible and rigid substrates utilizing reusable patterned mask. CO2 laser-cut glass-based mask is fabricated and assembled with the su...

Plasma electrolytic oxidation (PEO) or microarc oxidation process has been carried out on Ti6Al4V substrate in electrolytic bath containing sodium silicate and sodium hypophosphate. The phase composition, microstructure and roughness of the PEO coating are examined by x-ray diffraction, scanning electron microscopy and profilometry techniques, resp...

We have fabricated VO2 nano-columns (NCs) on the aluminized quartz glass substrates using glancing angle deposition (GLAD) technique inside the electron beam (e-beam) evaporator chamber. An e-beam deposited TiO2 thin cap-layer has been introduced on the top of the VO2 NCs to protect VO2 phase which is usually unstable and turns to stable higher oxi...

Atmospheric plasma spraying (APS) technique was utilized to deposit pure alumina and alumina–titania-based composite coatings on the 304 stainless steel substrates. Here, in the present work, one of the important process parameters viz. stand-off distance (SOD) was altered as 70, 90, and 110 mm. The percentage of titania was increased from 13 wt% (...

Present study reports the detailed nanomechanical and corrosion behaviours of crystalline and amorphous plasma electrolytic oxidation (PEO) coatings developed on Aluminium alloy-6061. The concentration of sodium silicate in the electrolyte is tailored to achieve crystalline and amorphous natures of the PEO coatings. X-ray diffraction (XRD), scannin...

Nano-scale load (P) dependency of fracture toughness (K1C) of indium tin oxide (ITO) coating on silicon (Si) substrate is evaluated by nanoindentation based direct and energy methods. A Berkovich triangular diamond nanoindenter is used with nine different P values e.g., 10, 15, 20, 30, 40, 50, 100, 150 and 200 mN. Extensive utilization of both opti...

Here, we investigate the effect of temperature on solution combustion synthesized MnFe2O4 nanoparticles (NPs) as supercapacitor electrode material that would affect the structural, optical, electrochemical, magnetic and sensing properties. The variation in temperature influences the structure and morphology of synthesized NPs which in turn produces...

Transparent super-hydrophobic monolithic silica aerogels are prepared by the cost-effective ambient pressure drying. The drying of aerogel is performed at various temperatures ranging from 25 to 200°C. Oxidation states of different silica aerogels are investigated by XPS which shows the presence of both SiO and SiO2 phases. Thermal stability of hyd...

The present pandemic coronavirus disease 2019 (COVID-19) becomes a serious concern of global health threat which is elicited by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This paper focuses on a hitherto untouched material’s engineering issue in human scientific fight against the well-known COVID-19. We show here the challenges a...

Silicon carbide (SiC) ceramic exhibits several outstanding properties, such as superior chemical and thermal stabilities, high radiation resistance and low thermal expansion, that qualify it as a prime candidate for space applications. Optical quality with surface figure accuracy of the order of 60 nm peak-to-valley (PV) and micro-roughness (root-m...

Mineral precipitation via microbial activity is a well-known process with applications in various fields. This relevance of microbially induced calcite precipitation (MICP) has pushed researchers to explore various naturally occurring MICP capable bacterial strains. The present study was performed to explore the efficiency of microbially induced ca...

In this work, we show that Microbial Induced Calcite Precipitation (MICP) can be used for making consolidated structures – space bricks – using lunar soil simulant (LSS). S. pasteurii was used as a bacterial strain to initiate MICP process via ureolytic pathway. An admixture of a naturally occurring biopolymer (guar gum) and a structural reinforcem...

Present work reports thermal conductivity measurement in a commercial soda–lime–silica glass substrate by the transient 3\(\omega\) method using a unique, custom-built in-house setup. Most importantly, a micro-heater (MH) cum temperature sensor is fabricated for this purpose. At first the MH-patterned mask is developed by CO2 laser cutting techniqu...

DC magnetron co-sputtering technique is utilised to develop reflective Ag- and Al-based metal films co-sputtered with Ni deposited on quartz glass substrates. The sputtered films are characterised by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques to investigate microstructur...

Alumina–25 wt-% zirconia (AZ) coatings were deposited on AISI304 stainless steel substrates by atmospheric plasma spraying (APS) technique with three different stand-off distances (SOD) namely, 75, 100 and 125 mm. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were utilized to study the phases and microstructures of the c...

We present results of our investigation of microbial induced calcite precipitation for manufacturing 'space bricks and a proposal for study of this activity in low-earth orbit (LEO). Sporosarcina pasteurii, a urease producing bacterial strain was used to consolidate lunar simulant soil (LSS) in the form of a 'brick' with non-trivial strength proper...

Alumina and zirconia coatings along with three combinations of alumina-zirconia (AZ) composite coatings are deposited on AISI304 by atmospheric plasma spraying (APS) technique. The AZ coatings are developed on the alumina rich side by varying zirconia content (e.g. 5%, 15% and 25%). To investigate the phases , X-ray diffraction technique is utilize...

We report the development, thorough characterizations and space worthiness studies of multifunctional aluminized film as x-ray intensity filter for space-based payloads, suitably designed to place in Sun–Earth Lagrangian (L1) point. The L1 point is the ideal location for uninterrupted observation of Sun to study the solar flares in hard x-rays. For...

The present study was performed to explore the efficiency of microbially induced calcite precipitation (MICP) via locally isolated bacterial strains. Strains were isolated from soil and were screened for urease activity as well as microbial precipitation. Among all screened isolates, a carbonate precipitating soil bacterium was subjected for 16S rR...

Doped and co-doped vanadium oxide (VO) thin films were deposited on quartz substrates with varying concentrations of doping elements by sol-gel spin coating technique. The VO thin films were characterized by the X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), cross-sectional FESEM and X-ray photoelectron spectroscopy (...

The present work reports the development of super-hydrophobic and optically opaque monolith silica aerogel that float in water. The opaque silica aerogels were prepared by the two step sol-gel process using tetraethoxysilane (TEOS) as silica precursor followed by cost effective ambient pressure drying with various aging solutions. The surface textu...

Preparation of highly luminescent glasses involves expensive and complicated processes and usually requires high temperature. In this work, we show that luminescent silicon (Si NP) embedded silicate gel glasses can be developed under near-ambient conditions by a remarkably simple, one-pot strategy, without using any sophisticated instrumentation or...

Nanoindentation of Hair Fiber: A Tough Hierarchical Layered Architecture

Natural nano-bio-hybrid composite materials, for example, bone, teeth, scale, shell, hair [1–10], etc., provide a different arrangement of material structures at various length scales that assist to perform various mechanical, biological, and chemical functions. These multifunctional or multi-objective properties of the natural hybrid composite str...

Smooth, uniform mixed valance vanadium oxide (VO) thin films are grown on flexible, transparent Kapton and opaque Al6061 substrates by the spin coating technique at a constant rpm of 3000. Various elements e.g., F, Ti, Mo and W are utilized for doping and co-doping of VO. All the spin coated films are heat treated in a vacuum. Other than the doping...

Phase pure, mesoporous, and crystalline V2O5 is synthesized by acid hydrolysis technique and subsequently heat treatment is carried out at 450, 500, 550, and 600 °C in air. The as-synthesized and heat-treated powders are thoroughly studied by X-ray diffraction, electron microscopy, dynamic light scattering, and spectroscopic techniques. A unique mo...

Germanium coated black polyimide (GBP) is often used as passive thermal control element for sunshield membrane of satellite antenna. However, GBP degrades fast while there is no protective coating applied. The present work is aimed towards the development of protective films which could hinder the degradation of GBP. At the same time, the basic cha...

Solar selective colored chromium oxide coatings were prepared on the SS304 substrate through the electrochemical deposition route to provide more options and flexibility in aesthetically design solar absorbers with acceptable energy performance. The variation of colors in the coatings was achieved by varying the coating thickness as a function of d...

Acquiring good adhesion of ITO thin films on polymer substrate is a major concern, especially for space related applications. Delamination of ITO coating on these polymers can seriously damage the spacecraft. This paper presents the development of highly transparent and conducting ITO thin films on as-received and surface treated fluorinated ethyle...

Acquiring good adhesion of ITO thin films on polymer substrate is a major concern, especially for space related applications. Delamination of ITO coating on these polymers can seriously damage the spacecraft. This paper presents the development of highly transparent and conducting ITO thin films on as-received and surface treated fluorinated ethyle...

The feasibility of utilizing commercially available silica aerogel-based flexible composite blankets as passive thermal control element in applications such as extraterrestrial environments is investigated. Differential scanning calorimetry showed that aerogel blanket was thermally stable over – 150 to 126 °C. The outgassing behavior, e.g., total m...

Smooth, uniform and crystalline vanadium oxide thin films were deposited on quartz by spin coating technique with four different rpm i.e., 1000, 2000, 3000 and 4000 and subsequently post annealed at 350, 450 and 550 °C in vacuum. Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD)...

Transparent and conducting ITO/Ag/ITO (IAI) multilayer coatings were deposited on glass and flexible fluorinated ethylene propylene (FEP) substrates by reactive sputtering using metallic In:Sn (90%:10%) and Ag targets at room temperature. Middle Ag layer thickness was optimized to obtain maximum figure of merit (ϕ) and the optimum Ag layer thicknes...

The damping capacity of plasma sprayed alumina (Al2O3) coatings on AISI 304 stainless steel was investigated in this study as a function of particle size of the starting alumina powder. The coatings were prepared from different sizes alumina powder using commercial air plasma spraying (APS) technique. The damping properties of coated samples were c...

A scalable, cost effective synthesis of reduced graphene oxide (RGO)-magnesium oxide (MgO) hybrid nanocomposite (RGOMOHNC) is reported in the present work. The process involves an in-situ sonication method in aqueous medium at room temperature e.g., 30. °C. The as synthesized graphene oxide (GO) and RGOMOHNC powders are characterized by the XRD, FE...

Aditya-L1 mission will carry two high-spectral resolution X-ray spectrometers to study solar flares. The soft X-ray spectrometer will cover the energy range from 1 to 30 keV, while the hard X-ray spectrometer will cover from 10 to 150 keV. These two instruments together will provide opportunities to study the plasma parameters during solar flares a...

Present study reports the effect of vacuum (10⁻⁵ mbar) heat treatment (300 °C–900 °C) on the microstructural, electronic, thermo-optical, mechanical and tribological properties of commercially pure (CP) titanium (Ti) ultra thin (75 µm) foil. Phase analysis and surface morphology of the as-received and vacuum heat treated Ti foil samples were invest...

A single layer antireflective, smart, crystalline and nanocolumnar pulsed RF magnetron sputtered vanadium oxide-molybdenum oxide thin film on silicon is proposed for the alternate material for silicon based futuristic solar cell application. The VO-MO film with 130 nm thickness grown at 200 W shows significant low reflectance (1% within the 500-600...

The soft chemical synthesis of self-assembled magnesium hydroxide (Mg(OH)2) nanoplatelets with surface area as high as about 300 m² g⁻¹ was achieved in the present work. The nanopowders such as MHN, MHCl, MHBr were synthesized at ~30 °C without using any catalyst or surfactant using, respectively, precursor solutions of Mg(NO3)2, MgCl2, MgBr2 and c...

Silica aerogel is a unique ultra light weight nano porous material which offers superior thermal insulation property as compared to the conventional thermal insulating materials. It can be applied not only for ground and aerospace applications but also in low and high temperatures and pressure regimes. Aerogel granules and monolith are synthesized...

Present study reports for the first time laser cutting of multilayered coatings on both side of ultra thin (i.e., 75 µm) glass substrate based rigid optical solar reflector (OSR) for spacecraft thermal control application. The optimization of cutting parameters was carried out as a function of laser power, cutting speed and number of cutting passes...

Molybdenum doped vanadium oxide film on quartz and silicon substrates are grown by pulsed RF magnetron sputtering method. Surface morphology, phase analysis and oxide states are investigated by field emission scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy techniques, respectively. Crystalline nature of the film...

The present work examined the efficacy of designed Mg(OH)2 nano-platelet assembly (DMGHNPA) for toxic Cu(II) waste removal from water. For this purpose, DMGHNPA with surface area as high as 237 m².g⁻¹ was synthesized by a very simple and cost effective method at room temperature. The results showed that at concentration range of 80–1000 mg.l⁻¹, ext...

Vanadium oxide-molybdenum oxide (VO-MO) thin (21–475 nm) films were grown on quartz and silicon substrates by pulsed RF magnetron sputtering technique by altering the RF power from 100 to 600 W. Crystalline VO-MO thin films showed the mixed phases of vanadium oxides e.g., V2O5, V2O3 and VO2 along with MoO3. Reversible or smart transition was found...

Vanadium oxide films, deposited on aluminium (Al), titanium (Ti) and tantalum (Ta) metal substrates by pulsed RF magnetron sputtering at a working pressure of 1.5 x10−2 mbar at room temperature are found to display mixed crystalline vanadium oxide phases viz., VO2, V2O3, V2O5.The films have been characterized by field-emission scanning electron mic...

Vanadium oxide thin films were deposited on quartz substrate by pulsed RF magnetron sputtering technique at 400-600Wand subsequently annealed at 100 °Cin vacuum (1.5×10⁻⁵ mbar). Phase analysis, surface morphology and topology of the films e.g., both as-deposited and annealed were investigated by X-ray diffraction, field emission scanning electron m...

The purpose of this present study was to evaluate the effect of vacuum (i.e., 105 mbar) heat treatment at 300 to 1100 °Con morphological, thermo-optical, mechanical and tribological properties of 75 m thin SS304 foils. Microstructural, morphological and surface properties of the foils were characterized by field emission scanning electron microscop...

The present work reports the nanomechanical behavior of a pulsed radio frequency (RF) magnetron sputtered vanadium pentoxide (V2O5) film deposited on silicon (Si) substrate using a combination of nanoindentation experiments and a finite element model (FEM). Deposited V2O5 film is characterized by x-ray diffraction (XRD), nanoprofilometry, field emi...

The major areas of applications of the composite materials today encompass fields as wide as wind energy to marine to construction to aerospace to strategic areas. Apart from such specialized fields the major composite market blooms out of their extensive exploitations in the automotive, sporting goods, pipes, tanks, chemicals, fertilizers and many...

Vanadium oxide thin films on silicon (Si) substrate are grown by pulsed radio frequency (RF) magnetron sputtering technique at RF power in the range of 100–700 W at room temperature. Deposited thin films are characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techn...

This work reports the loading rate effect on nanohardness of sapphire. The intrinsic nanoscale contact deformation resistance of sapphire increased with the loading rates following empirical power law dependence with a positive exponent. The results showed a significant enhancement (e.g., ~66%) of the nanohardness of sapphire with the increase in l...

The germanium (Ge) coated Kapton i.e., polyimide substrate based thermal blanket or membrane is often utilized to spread over the carbon fiber reinforced plastic (CFRP) antenna on the sun-facing side of GEO satellites and it act as sunshield. However, Ge surface is observed to degrade in ambient atmosphere and during implementation. The Ge coating...

The development of vanadium oxidemolybdenum oxide (VO-MO) by pulsed RF reactive magnetron sputtering technique at 6 different RF power from 100 W – 600 W using a high purity (99.995%) V2O5 target in the argon atmosphere of 1.5x10-2 mbar on quartz substrate is described in the present communication. Subsequently, investigation is carried out to und...

The development of vanadium oxidemolybdenum oxide (VO-MO) by pulsed RF reactive magnetron sputtering technique at 6 different RF power from 100 W – 600 W using a high purity (99.995%) V2O5 target in the argon atmosphere of 1.5x10-2 mbar on quartz substrate is described in the present communication. Subsequently, investigation is carried out to und...

This work evaluates the nanohardness of a single alumina grain for a coarse grain alumina ceramic of ∼10 μgrain size. The results reveal that the nanoscale contact deformation resistance of the single grain has a unique self-adjusting characteristic. It increases in response to enhancement in the externally applied load. The nanoscale contact defor...

A combined nanoindentation experiment and finite element modeling (FEM) approach was utilized in the present work to evaluate the effects of variations in the ratio (h/t) of indentation depth (h) to film thickness (t) on the nanomechanical behavior of 2.3-6.2 μm vanadium pentoxide (V2O5) films. The soft V2O5 films were deposited by pulsed radio fre...

In this report we present the systematic study on nanomechanical and tribological properties of heat treated (300-900°C) commercially Pure (CP) Titanium (Ti) thin foil (i.e. 75 m thickness) under vacuum condition i.e. 10-5 mbar. Nanomechanical properties i.e., nanohardness and elastic modulus were evaluated by Nanoindentation method. Tribological...

The purpose of this study was to evaluate the effect of vacuum (i.e. 10-5 mbar) heat treatment (300-1100°C) on Nano-mechanical and tribological properties of SS 304 thin foil (75 m thickness). For this purpose, Nano-mechanical properties (i.e., nanohardness and young's modulus) of as received SS304 and vacuum heat treated samples were evaluated by...

Satellites operating in earth orbit are subjected to harsh space environment. To ensure the payloads and the electronic equipments performs to its intended mission life, satellites need to be protected from harsh fluctuating environment and achieve thermal balance by implementing passive thermal control elements like multilayer insulation (MLI), th...