Roughness Area Research Articles

Unveiling K-storage property of temperature-depended Fe-based metal organic terephthalate in KFSI-based electrolyte

Constructing suitable anode materials with high specific capacity, cyclic performance as well as low-cost have been mainly restricted by the large K+radius for inorganic counterparts in potassium-ion batteries recently. Herein, the potassium storage performance and reaction mechanism of temperature-depended organic iron terephthalate (FeC8H4O4) were comparatively investigated in difluoro-sulfonimide potassium (KFSI)-based ester and ether electrolytes. The as-prepared FeC8H4O4–250 with rough surface area and larger specific surface area, showed the best electrochemical performance than that of FeC8H4O4–150 and FeC8H4O4. It was disclosed that the potassium storage mechanism of FeC8H4O4–250 is based on the reversible enolation reaction of carbonyl and the conversion of Fe2+ into Fe nanoparticles, consequently resulting in high specific capacity. In addition, the results suggest that FeC8H4O4–250 exhibits better cycling stability in KFSI/DME electrolyte than in KFSI/EC+DEC, which is mainly because the salts and solvents in KFSI/EC+DEC contribute to the formation of a stable and robust SEI that inhibits the decomposition of the electrolyte. Our work is of significant to explore high-performance electrode materials for next-generation energy storage systems.

Growth mechanism of oxide layer on Ti-6Al-4 V substrate with different surface topographies during the early stage of micro-arc oxidation

The aim of this work was to explore the effect of microscopic surface topographies of the Ti-6Al-4 V alloy on the coating growth behaviour during the initial stages of micro-arc oxidation (MAO). Firstly, MAO treatments were carried out on the surfaces of Ti-6Al-4 V alloys with different surface morphologies for 5, 10 and 15 min respectively. Second, the effects of substrate topographies on the roughness, porosity, thickness, and microstructure of the coatings were studied. Then, the corrosion resistance of the MAO-treated titanium alloys was assessed by electrochemical analysis. Finally, the formation mechanisms and morphological results of the oxide layer were discussed and illustrated graphically. The results showed that the surface morphologies of the substrate affected the micro-arc discharge behaviour during the process of oxidation. Notably, rough areas on the substrate surface facilitated the breakdown of the passivation film, which was evidenced by the early appearance of plasma discharges in these areas. However, surface morphology with uneven distribution of pores observed in the oxide layer formed by the rough substrate. The coatings grown on the grooves were more porous than those grown in other areas, due to the non-uniformity of the micro-discharge on the rough substrate surface.

A comprehensive mortise and tenon structure selection method based on Pugh's controlled convergence and rough Z-number MABAC method.

Mortise and tenon joints are widely used in the building and furniture industries because of their excellent mechanical and eco-friendly properties. In real-life cases, there are usually many available alternative structures for a joint area, it is a challenge to select a proper structure from massively available alternatives. This paper aims to select a proper multiple attribute decision-making method based on massive alternatives and unreliable, uncertain and subjective information. Pugh's controlled convergence, rough number, Z-number, consistency theory and Shannon entropy are integrated and proposed an improved rough Z-number Multi-Attributive Border Approximation Area Comparison (MABAC) method. Firstly, Pugh's controlled convergence is a selection method, simple and rapid, presented in the first phase to eliminate most of the alternatives. In the second phase, an integrated method is proposed. The consistency theory, distance measurement and the Z-number are initially aggregated to calculate the expert weight. The entropy method is then presented to determine the criteria weight. The alternatives are then ranked and the optimal mortise and tenon joint is selected based on the rough Z-number MABAC method. A real-life case is presented, and the proposed method is implemented in the joint of a bucket cabinet. Finally, the efficiency and effectiveness of the proposed method are proved by the case, sensitivity analysis and related comparisons.

Assembly of NiFe-PBA nanoparticles on nanoflower-like NiFe-PBA@IF as enhanced oxygen evolution electrocatalyst at room temperature

Oxygen Evolution Reaction (OER) catalysts that overcome low energy barriers to improve the reaction efficiency of the OER are important for the development of future green energy sources. Herein, NiFe-PBA@IF layered nanoflowers were successfully prepared by etching iron foam (IF) using Prussian blue-like (PBA) material as a precursor. Notably, the fractured PBA nanosheets prepared by etching at room temperature had a suitable growth gradient and growth environment with the homogeneous nucleation environment, compared to the conventional method. In this environment, a layered NiFe-PBA structure can be formed on the surface of IF, enabling efficient green synthesis, reducing ecological and economic costs, and providing a clear source of catalytic activity. More importantly, NiFe-PBA@IF has a nanoparticle structure anchored on NiFe-PBA stacked nanoflowers, which can expand the surface roughness and electrochemical active area of the sample, so the OER performance in 1 M KOH is 253 mV@10 mA·cm−2. The green and direct synthesis of PBA electrocatalysts can provide new ideas for the efficient synthesis of other OER electrocatalysts at room temperature and will further provide an effective template for the industrial application of OER electrocatalysts.

Fretting tribocorrosion properties of anodized TiNbSn implant alloy

Titanium and its alloys have poor wear resistance, and the biological response to generated wear debris leads to aseptic loosing and pathological bone resorption. In the fretting wear of artificial hip joints, a significant part of the wear surface is contacted by elastic deformation, and electrochemical anodization is a promising method to control the mechanical properties of the surface and improve wear resistance. To suppress wear debris generation and metal ions elution from implant materials into body fluids, the tribocorrosion properties of a newly developed anodized TiNbSn implant alloy were evaluated in the presence of simulated body fluid and compared to those of pure Ti. During anodization under high voltage, spark discharge occurred due to dielectric breakdown occurred for the TiNbSn electrode, but not for the Ti electrode. The primary phase of the anodic oxide layer on TiNbSn alloy was rutile TiO2, whereas that on Ti was anatase TiO2. The anodic oxide layer on TiNbSn had a higher thickness, roughness, and surface area than that on anodized Ti. In addition, the hardness and exfoliation strength were higher than those of Ti. The coefficient of friction of anodized TiNbSn in fretting tests was similar or slightly lower than that of anodized Ti, and the open circuit potential remained unchanged for anodized TiNbSn but shifted to a more negative voltage for anodized Ti. The results suggest that the hard and strongly-adhered rutile TiO2 on TiNbSn formed by spark discharge during the high-voltage anodization process improves fretting wear resistance and reduces the generation of wear debris and elution of metal ions.

Elastohydrodynamic lubrication model and failure test for micro-contact thermodynamic characteristics of friction interface

A micro-contact thermodynamic model is proposed to study the interfacial characteristics in wet friction pair based on Elastohydrodynamic Lubrication (EHL) theory. The study takes into account the asperity elastic-plastic deformation, establishing an improved model with high accuracy in verifications with experimental data and existing model. With this optimized micro-contact thermodynamic model, we systematically discussed the influence of sliding speed, oil temperature, and average surface pressure on thermodynamic behaviors such as rough contact area, pressure distribution, and temperature distribution. Additionally, experimental investigations revealed the complex failure mechanism of the friction disc. Specifically, during the failure process, the friction coefficient and the radial temperature difference gradually increase. The metal oxides form on the surface, and the graphite distribution is gradually dispersed.

Investigation of quasi-cleavage in a hydrogen charged maraging stainless steel

Slow strain rate tests on hydrogen-containing specimens of PH13–8Mo maraging stainless steel showed H-assisted subcritical quasi-cleavage cracking, accelerating material failure. Fractographic analysis revealed that quasi-cleavage is composed of flat brittle areas and rougher areas. Electron backscatter diffraction (EBSD) was performed on a secondary subcritically grown crack. High resolution EBSD showed significant crystal lattice rotation, hence consequential plastic deformation, concentrated between the main crack tip and the cracks located ahead of it. Quasi-cleavage consisted of {100} cleavage cracks connected by ductile ridges, suggesting a discontinuous mechanism, involving re-initiation of new cleavage cracks ahead the main crack tip.

Formation of fine granular area in a non‐defect matrix of austenitic stainless steel during very high cycle fatigue

AbstractA fine granular area, FGA, is a typical phenomenon observed at the very high cycle fatigue fracture crack origin with a subsurface defect in the material. The FGA has been widely investigated, and different mechanisms have been proposed. In this paper, the formation of FGA in a non‐defect matrix of one austenitic steel during very high cycle fatigue was studied using a progressive stepwise load‐increasing method and electron scanning microscopy/electron channeling contrast imaging (ECCI) technique. A nano rough surface area or FGA at the fatigue crack origin has been observed in the subsurface matrix without any defect. It is a new phenomenon. A mechanism was proposed using the dislocation plasticity theory. The formation of FGA in a non‐defect matrix is a localized plasticity exhausting process by strain localization, grain fragmentation, stress concentration and nano crack initiation and propagation along low‐angle grain boundaries.

Fabrication and Characterization of Nickel Nanoparticles using Calotropis gigantea for Antimalarial Applications

Malaria diagnosis using sophisticated methods is highly expensive and time-consuming. The development of sensitive, selective, robust, accurate, fast and low-cost clinical diagnosis techniques has been a major focus of researchers in recent years. In this work, nickel nanoparticles have been synthesized successfully using Calotropis gigantea leaf extract, by Co-precipitation method and then characterized by Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Energy Dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR) and Ultraviolet-visible (UV-Vis.) spectroscopic techniques. FT-IR spectra showed a sharp peak at 699 cm -1 and a broad peak ranging from 2500 - 3500 cm-1 ensuring the construction of nickel nanoparticles. X-ray Diffraction pattern revealed a face-centered cubic structure. The SEM image has shown the spherical structure with a rough area. The results obtained were satisfactory in terms of antimalarial applications of the nickel nanoparticles.

Microstructure and oxidation resistant of Si–NbSi2 coating on Nb substrate at 800°C and 1000°C

The Si–NbSi2 composite coating with a smooth surface was successfully prepared on Nb substrate by hot dip silicon-plating (HDS) technology. The composite coating is composed of Si outer layer, NbSi2 interlayer and Nb5Si3 interfacial layer. And the average surface roughness (RSa) and specific surface area growth rate (Sdr) are only 0.275 μm and 2.85%, respectively. The cyclic oxidation test shows that the Si–NbSi2 composite coating has a very excellent oxidative resistance after oxidation at 800 °C for different times. After oxidation for 40 h, the Δm/S and oxide layer thickness of the coating are only 3.72 mg/cm2 and 8 μm, respectively. After oxidation at 1000 °C for 20 h, the coating surface is almost completely covered by a dense SiO2 layer, the Δm/S and oxide layer thickness of the coating are 7.28 mg/cm2 and 15 μm, respectively. The Si–NbSi2 composite coating presents good self-healing ability and excellent oxidation resistance, which can significantly prolong the service life of bare Nb in oxidation environment.

Experimental Study of Sound Absorption Coefficient Characteristics of Oil Palm Frond Reinforced Composite

This study aims to investigate the capability of sound absorption coefficient (SAC) of oil palm frond (OPF) composite. Also, to characterize the fiber surface without treatment and with alkali treatment. Two parameters were formulated to characterize the SAC ability of the OPF composite: chemical treatment and density of composite. The composite was manufactured from a waste OPF as a reinforcement and urea-formaldehyde (UF) resin as a matrix. The fibers were blended with UF 10% (weight fraction) and formed by hot-pressing under the pressure of 9 tons at 140°C for 5mn. The SAC was measured by the impedance tube respected with ASTM 1050 (the transfer function method) within the frequency of 125-6400 Hz. Morphological analysis is investigated by scanning electron microscopy (SEM) on untreated and alkali-treated OPF fiber. The measurement data were obtained and compared with different densities and treatments. It reveals that the SAC of OPF composite was proportion to density and alkali-treated. The SAC worsens as the composite becomes dense due to the greater density. The treated fibers have more roughness and friction area than untreated fiber; thereby, the incidence of sound energy rapidly dissipates to thermal energy, causing improved SAC performance

Industrial approach to circularity of polymer composites: Processing, characterization, mechanical testing, and wear regression

Cotton, polyester, and polyethylene terephthalate are the most common types of polymers that produce huge wastes. The circularity of these post-consumer (PC) waste faces operational problems during processing. In this innovative research, the relationship between circularity, surface characterization, mechanical and tribological testing of fiber reinforced (cotton, polyester), and particulate (polyethylene terephthalate) composites is explored for industrial pilot production. Cutting model can control the size of fibers during grinding. The fiber reinforced composites (FRCs) with 10% (by weight) fiber loadings are found as operational candidates for structural, automotive, and medical applications due to suitable tensile strength (26–29 MPa), percentage of extension (10%) and abrasive wear (3 × 10−6 mm3/Nm). An increase in fiber content produces micro-defects like asperities, rough areas, voids, cracks, and pits in recycled composites. Therefore, the particulate and FRCs with 40% (by weight) fiber loadings become hard and brittle. However, these composites (especially with 40% wt. fiber loadings) exhibit reasonable elastic modulus (1526–2751 MPa) and abrasive wear (6.5 × 10−6 mm3/Nm). The ductile to brittle transition effect has appeared in all composites (with 30% wt. fiber content) due to continuous fiber addition, micro-defects creation and dual phase presence. In conclusion, natural and synthetic PC wastes can be utilized for sustainable processing of commercial polymer composites. Moreover, injection molding, polymer characterization, tensile testing, abrasion evaluation, and regression analysis can be introduced for the transformation of open-loop into closed-loop manufacturing.

Polyhydroxybutyrate (PHB) in nanoparticulate form improves physical and biological performance of scaffolds

Polyhydroxyalkanoates (PHAs) are natural polyesters produced by microorganisms as a source of intracellular energy reserves. Due to their desirable material characteristics, these polymers have been thoroughly investigated for tissue engineering and drug delivery applications. A tissue engineering scaffold serves as a substitute of the native extracellular matrix (ECM) and plays a crucial role in tissue regeneration by providing temporary support for cells during natural ECM formation. In this study, porous, biodegradable scaffolds were prepared using native polyhydroxybutyrate (PHB) and PHB in nanoparticulate form using salt leaching method, to investigate the differences in the physicochemical properties such as crystallinity, hydrophobicity, surface morphology, roughness, and surface area and biological properties of the prepared scaffolds. As per the BET analysis, PHB nanoparticles-based (PHBN) scaffolds presented a significant difference in the surface area as compare to PHB scaffolds. PHBN scaffolds showed decreased crystallinity and improved mechanical strength as compared to PHB scaffolds. Thermogravimetry analysis shows delayed degradation of PHBN scaffolds. An examination of Vero cell lines' cell viability and adhesion over time revealed enhanced performance of PHBN scaffolds. Our research suggests that scaffold made of PHB nanoparticles could serve as a superior material for tissue engineering applications than its native form.

Deep Reinforcement Learning-Based Failure-Safe Motion Planning for a 4-Wheeled 2-Steering Lunar Rover

The growing trend of onboard computational autonomy has increased the need for self-reliant rovers (SRRs) with high efficiency for unmanned rover activities. Mobility is directly associated with a successful execution mission, thus fault response for actuator failures is highly crucial for planetary exploration rovers in such a trend. However, most of the existing mobility health management systems for rovers have focused on fault diagnosis and protection sequences that are determined by human operators through ground-in-the-loop solutions. This paper presents a special four-wheeled two-steering lunar rover with a modified explicit steering mechanism, where each left and right wheel is controlled by only two actuators. Under these constraints, a new motion planning method that combines reinforcement learning with the rover’s kinematic model without the need for dynamics modeling is devised. A failure-safe algorithm is proposed to address the critical loss of mobility in the case of steering motor failure, by expanding the devised motion planning method, which is designed to ensure mobility for mission execution in a four-wheeled rover. The algorithm’s performance and applicability are validated through simulations on high-slip terrain scenarios caused by steering motor failure and compared with a conventional control method in terms of reliability. This simulation validation serves as a preliminary study toward future works on deformable terrain such as rough or soft areas and optimization of the deep neural network’s weight factor for fine-tuning in real experiments. The failure-safe motion planning provides valuable insights as a first-step approach toward developing autonomous recovery strategies for rover mobility.

Endoscopically assisted bone lid surgery for foreign body removal from the maxillary sinus and maxillary bone

AbstractBackgroundBone lid surgery (BLS) is commonly used for the removal of foreign bodies from the maxillary sinus.Case presentationImaging tests showed the presence of a foreign body in the maxillary bone, close to the maxillary sinus floor, and in the maxillary sinus. Removal of this foreign body was performed using endoscopically assisted BLS. Rough areas distinctly different from the surrounding bone were detected via endoscopy was removed.ConclusionWe assessed the effectiveness of endoscopically assisted BLS in the removal of foreign bodies from the maxillary sinus and maxillary bone.

Modeling of horizontal steam injection in a water pool

A comprehensive understanding of the direct contact condensation (DCC) phenomena of steam discharged into a subcooled water pool is essential for the nuclear engineering field. DCC is the most rapid and efficient way to condense high-pressure and high-temperature steam with simple engineering systems. However, the pressure oscillation due to the rapid condensation and small length and time scales of turbulent two-phase flow make the investigation of DCC phenomena challenging either by experiments or with numerical simulations.This paper presents the computational fluid dynamics (CFD) simulations of the small-scale separate effect test facility (SEF-POOL) experiment of Lappeenranta-Lahti University of Technology (LUT University). In the SEF-POOL test, the steam was injected using the orifice of a diameter of 16 mm. All simulations were performed by employing the compressible two-phase solver of OpenFOAM which was based on the Eulerian–Eulerian two-fluid approach. The interfacial heat transfer between steam and water was modeled by using the Nusselt number formulation of Coste (2004). The Rayleigh–Taylor interfacial (RTI) area model of Pellegrini et al. (2015) was applied for the interfacial area modeling. In this work, the formation and collapse of the steam bubbles are studied using the extended pattern recognition based image analysis algorithm. The pattern recognition (PR) algorithm is based on the video material recorded during the SEF-INF2 experiment of the SEF-POOL test facility.The presented study show that if the two-phase interface is rough and smear into the subgrid scale, the interfacial area density calculation solely with the volume fraction gradient is inadequate for predicting rapid condensation rates. Results indicate that rapid and high interfacial accelerations in DCC trigger interfacial instabilities which increased the interface roughness and total interfacial area consequently. Thus, interfacial area modeling with the RTI increased the total interfacial heat transfer rate in the simulations. The achieved results exhibit that the selected modeling approach captured the rapid bubbling condensation oscillation mode of the SEF-POOL test. Presented results demonstrate that image analysis and pattern recognition have great potential in thermal-hydraulic research that can be beneficial for direct contact condensation and phase-interface dynamics model development.

Nanosphere-structured hierarchically porous PVDF-HFP fabric for passive daytime radiative cooling via one-step water vapor-induced phase separation

Growing demand for efficient and economical cooling for indoor as well as outdoor applications, especially personal cooling in outdoor environments, is a major global challenge today. Currently, tailored optical structures with spectral selectivity are being used as cooling strategies. However, developing these photonic structures generally requires sophisticated multi-step manufacturing processes and use of multiple solvents which limits their acceptability for large-scale production and cost-effectiveness. Therefore, for the first time, herein we report the fabrication of nanosphere-structured hierarchically porous poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) fibrous fabric via a facile one-step electrospinning process based on water vapor-induced phase separation (WVIPS) technique using single solvent. The fabricated fabric with interconnected nanospheres structure and hierarchically porous fibers possessed large roughness and high specific surface area. Cooling performance of the fabricated PVDF-HFP fabrics was evaluated using skin simulators to mimic human body. The as-prepared PVDF-HFP fabric exhibits a superior average solar reflectance (∼93.7 %) and infrared emittance (∼91.9 %), yielding a temperature drop of ∼19.8 °C and ∼13.2 °C compared to the bare skin simulator and the one covered with cotton fabric, respectively, under solar intensity of ∼950 W m−2. Additionally, excellent hydrophobicity and adsorption make designed fabrics potentially suitable materials for not only radiative cooling but also for waterproof and filtration applications.

Effect of Implantoplasty on Roughness, Fatigue and Corrosion Behavior of Narrow Diameter Dental Implants.

Implantoplasty (IP) is used in dental implants with peri-implantitis and aims to remove threads and polish rough surfaces in order to prevent bacterial colonization. As a result of this procedure, implant strength might be compromised. We tested 20 tapered screw-shaped Ti6Al4V dental implants with a simulated bone loss of 50%. Ten implants underwent IP and 10 served as controls. Surface topography (Sa, Sz, Ssk, and Sdr) was analyzed with a confocal optical microscope. Subsequently, a minimum of four series of cyclic loads were applied with a servo-hydraulic mechanical testing machine (5 × 106 cycles at 15 Hz, between a maximal nominal value-starting at 529 N in the IP group and 735 N in the control group-and 10% of that force). We recorded the number of cycles until failure and the type of failure. Implant failure was analyzed by visual inspection and scanning electron microscopy. Open circuit potential and potenctiodynamic tests were carried out with high precision potentiostat using Hank's solution at 37 °C to evaluate the effect of the implantoplasty on the corrosion resistance. Implantoplasty significantly reduced the surface topography values (median) and interquartile range (IQR); Sa from 1.76 (IQR = 0.11) to 0.49 (IQR = 0.16), Sz from 20.98 (IQR = 8.14) to 8.19 (IQR = 4.16), Ssk from 0.01 (IQR = 0.34) to -0.74 (IQR = 0.53) and Sdr from 18.20 (IQR = 2.26) to 2.67 (IQR = 0.87). The fatigue limits of the control and implantoplasty groups were 551 N and 529 N, respectively. The scanning electron micrographs showed fatigue striations indicating fatigue failure. Besides, the fractographic analysis revealed a typical brittle intergranular fracture mechanism. The infinite life range of the dental implants evaluated was largely above the threshold of usual chewing forces. Implantoplasty seems to render a fairly smooth surface and has a limited impact on fatigue resistance. In addition, implantoplasty produces a decrease in the corrosion resistance of the implant. Corrosion current density from 0.019 μA/cm2 for as-received to 0.069 μA/cm2 in the interface smooth-roughened dental implant. These places between the machining and the rough area of the implant are the most susceptible, with the appearance of pitting.

Biofunctionalization of polyetheretherketone implant material by bone-forming peptide-2 immobilization

Polyetheretherketone (PEEK) has favorable biomechanical properties to be used as an implant material. Unfortunately, it is hydrophobic and does not promote cellular adhesion, which could result in poor integration with bone tissue. Bio-functionalization of PEEK surface with osteogenic peptides derived from bone extracellular matrix proteins is an excit-ing approach to encourage bone formation around the implant. In the current study, bone-forming peptide-2 was immo-bilized on PEEK surface using two different methods, using dopamine and a diglycidyl ether as conjugate compounds, respectively. Peptide quantification test revealed that the two strategies resulted in the most amount of peptides were attached with 0.5 mM concentration and no further peptides were grafted with a higher peptide concentration. Both methods showed good peptide stability after agitation in aqueous solution. Peptide grafting was confirmed with ATR-FTIR. Surface characterizations with AFM and wettability tests resulted in a significant increase in surface roughness and surface area ratio for the peptide-grafted PEEK compared to unmodified PEEK, which led to a signifi-cant enhancement in the wettability of the modified PEEK surface

Highly Heterogeneous Morphology of Cobalt Oxide Nanostructures for the Development of Sensitive and Selective Ascorbic Acid Non-Enzymatic Sensor

The surface tailored metal oxide nanostructures for the development of non-enzymatic sensors are highly demanded, but it is a big task due to the wide range of complexities during the growth process. The presented study focused on the surface modification of the heterogeneous morphology of cobalt oxide (Co3O4) prepared by the hydrothermal method. Further surface modification was conducted with the use of sodium citrate as a reducing and surface modifying agent for the Co3O4 nanostructures through the high density of oxygenated terminal groups from the citrate ions. The citrate ions enabled a significant surface modification of the Co3O4 nanostructures, which further improved the electrochemical properties of the Co3O4 material toward the design of the non-enzymatic ascorbic acid sensor in a phosphate buffer solution of pH 7.4. The morphology and crystal arrays of the Co3O4 nanostructures were studied by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) techniques. These physical characterizations showed the highly tailored surface features of Co3O4 nanostructures and a significant impact on the crystal properties. The electrochemical activity of Co3O4 was studied by chronoamperometry, linear sweep voltammetry, and cyclic voltammetry (CV) for the detection of ascorbic acid. The linear range of the proposed sensor was measured from 0.5 mM to 6.5 mM and a low limit of detection of 0.001 mM was also estimated. The presented Co3O4 nanostructures exhibited significant surface roughness and surface area, consequently playing a vital role toward the selective, sensitive, and stable detection of ascorbic acid. The use of a low cost surface modifying agent such as sodium citrate could be of great interest for the surface roughness and high surface area of nanostructured materials for the improved electrochemical properties for the biomedical, energy storage, and conversion systems.