Homogeneous Time Research Articles

Effect of Microporous Layer Ink Homogenisation on the Through-Plane Gas Permeability of PEFC Porous Media

The through-plane gas permeability and morphology of PEFC gas diffusion media (GDM) is investigated for different microporous layer (MPL) ink homogenisation techniques (bath sonication and magnetic stirring) for low- (Vulcan XC-72R) and high (Ketjenblack EC-300J)-surface-area carbon powders. The MPL composition is held constant at 80 wt.% carbon powder and 20 wt.% PTFE for a carbon loading of 1.0 mg cm−2. The MPL ink homogenisation time is held constant at two hours for both techniques and increased by one hour for bath sonication to compare with previous investigations. The results show that the through-plane gas permeability of the GDM is approximately doubled using magnetic stirring when compared with bath sonication for MPLs composed of Vulcan XC-72R, with a negligible change in surface morphology between the structures produced from either homogenisation technique. The variation in through-plane gas permeability is almost negligible for MPLs composed of Ketjenblack EC-300J compared with Vulcan XC-72R; however, MPL surface morphology changes considerably with bath sonication, producing smoother, less cracked surfaces compared to the large cracks produced via magnetic stirring for a large-surface-area carbon powder. An MPL ink sonication time of three hours results in a percentage reduction in through-plane gas permeability from the GDL substrate permeability by ~72% for Ketjenblack EC-300J compared to ~47% for two hours.

Application of Design of Experiment in the Optimization of Apixaban-Loaded Solid Lipid Nanoparticles: In Vitro and In Vivo Evaluation

Solid lipid nanoparticles (SLnPs) are usually utilized as lipid-based formulations for enhancing oral bioavailability of BCS class IV drugs. Accordingly, the objective of this work was to investigate the effect of formulation and processing variables on the properties of the developed SLnPs for oral delivery of apixaban. Randomized full factorial design (24) was employed for optimization of SLnPs. With two levels for each independent variable, four factors comprising both formulations and processing factors were chosen: the GMS content (A), the Tween 80 content (B), the homogenization time (C), and the content of poloxamer 188 used (D). The modified hot homogenization and sonication method was employed in the formulation of solid lipid nanoparticles loaded with apixaban (APX-SLnPs). The size of APX-SLnPs formulations was measured to lie between 116.7 and 1866 nm, polydispersity index ranged from 0.385 to 1, and zeta potential was discovered to be in the range of − 12.6 to − 38.6 mV. The entrapping efficiency of APX-SLnPs formulations was found to be in the range of 22.8 to 96.7%. The optimized formulation was evaluated in vivo after oral administration to rats. Oral administration of APX-SLnPs resulted in significant prolongation in bleeding time compared with both positive and negative control. This indicates the ability of this system to enhance drug therapeutic effect either by increasing intestinal absorption or trans-lymphatic transport. So, this study highlighted the capability of SLnPs to boost the pharmacological effect of apixaban.Graphical

Evaluation of a high-throughput H295R homogenous time resolved fluorescence assay for androgen and estrogen steroidogenesis screening

The H295R test guideline assay evaluates the effect of test substances on synthesis of 17β-estradiol (E2) and testosterone (T). The objective of this study was to leverage commercial immunoassay technology to develop a more efficient H295R assay to measure E2 and T levels in 384-well format. The resulting Homogenous Time Resolved Fluorescence assay platform (H295R-HTRF) was evaluated against a training set of 36 chemicals derived from the OECD inter-laboratory validation study, EPA guideline 890.1200 aromatase assay, and azole fungicides active in the HT-H295R assay. Quality control performance criteria were met for all conditions except E2 synthesis inhibition where low basal hormone synthesis was observed. Five proficiency chemicals were active for both the E2 and T endpoints, consistent with guideline classifications. Of the nine OECD core reference chemicals, 9/9 were concordant with outcomes for E2 and 7/9 for T. Likewise, 9/13 and 11/13 OECD supplemental chemicals were concordant with anticipated effects for E2 and T, respectively. Of the 10 azole fungicides screened, 7/10 for E2 and 8/10 for T exhibited concordant outcomes for inhibition. Generally, all active chemicals in the training set demonstrated equivalent or greater potency in the H295R-HTRF assay, supporting the sensitivity of the platform. The adaptation of HTRF technology to the H295R model provides an efficient way to evaluate E2 and T modulators in accordance with guideline specifications.

Identification of factors influencing the quality of extruded profiles using aluminum Recyclate-Based billets

The recycling of aluminium chips by direct processing of the chips in the extrusion process is a metal forming technique which requires less energy than remelting of the chips and prevents further material losses during the remelting process. For this purpose, chips contaminated with lubricant or cleaned chips can be used for the chip-based extrusion. Since the process parameters also influence each other and, in addition, the properties of the chips must be considered as additional parameters, which also have an influence on the success of the process and the quality of the profiles the determination of the factors influencing the process has not yet been completed. Due to previous investigations, it can be determined that the quality of the extruded profiles depends on the choice of the tool concept as well as the extrusion ratio. In contrast to previous studies investigating the influence of die design, chip geometry and compaction route, a porthole die was used in the present experiments. In these experiments, the process parameters such as extrusion speed, temperature, homogenization time were varied and their influence on the mechanical properties was evaluated. Furthermore, a new criterion is presented to evaluate the welding quality of the chips. In experimental as well as numerical investigations, the use of tensile tests and the evaluation of the weld quality showed that the mechanical properties of the profile vary over the cross-section independently of the process parameters. At the same time, the results have shown that in extrusion of chip-based billets, the yield strength, tensile strength and breaking elongation can be significantly influenced by the use of appropriate process parameters.

Exploring the mechanism of solid-state transformation σ → γ during homogenization in 7Mo super austenitic stainless steel

Topologically close-packed phases (TCP phase), with ordered dense-stacked structure, realize the atomic diffusion at high temperatures by forming the defects. In this study, we investigated the σ → γ transformation process at high temperature in cast 7Mo super austenitic stainless steel. Based on in-situ observation and microstructure analysis, it denoted that the modulated structure appeared in σ phase during the transformation process, which caused by the limited mobility of atoms. With extending homogenization time, the new γ phase formed at the boundaries of the modulated structure in σ phase. The size of the σ phase gradually decreased as new γ phase grew up. This discovery enriches the phase transformation mechanism of intermetallic compounds and provides a new sight for applying σ phase at high temperature.

Influence of Homogenization on Phase Transformations during Isothermal Aging of Inconel 718 Superalloys Fabricated by Additive Manufacturing and Suction Casting.

The attainment of the desired strength of the Inconel 718 superalloy heavily relies on the isothermal aging process, which plays a critical role in achieving the anticipated hardening effect. Surprisingly, there remains a dearth of dedicated studies investigating the influence of homogenization on phase transformations during the isothermal aging process, leaving a gap in the knowledge required to guide the design of post-heat treatment strategies. Addressing this gap, our work investigates the impact of homogenization time on phase transformations during isothermal aging at 730 °C in Inconel 718 alloys produced via additive manufacturing (AM) and suction casting (SC) methods. Intriguingly, we observe contrasting behaviors in the particle size of γ″ and γ' in aged samples, depending on the homogenization time and the alloy processing method. Specifically, in AM alloys, extended homogenization time leads to an increase in the particle size of γ″ and γ', whereas the opposite trend is observed in SC alloys. Furthermore, despite undergoing the same heat treatment, the AM alloys exhibit smaller particle sizes but higher precipitate number densities compared to the SC alloys, resulting in superior hardness. Notably, pronounced grain refinement during aging is evident in 1 h homogenized SC samples under 1180 °C, warranting further investigations into the underlying mechanisms. This study elucidates the crucial role of homogenization in attaining the desired microstructure following subsequent aging processes. Moreover, it offers novel insights for developing post-heat treatment strategies for superalloys.

Study on preparation and properties of Camellia oleifera seed oil microcapsules by complex coacervation and spray drying

The Camellia oleifera seed oil is popular among consumers for its high nutritional value, but the instability of lipid oxidation limits its wide application in practical situations. In this study, we used whey protein and three wall materials to make microcapsules by composite co-composition and spray-drying. The results showed that the best embedded method was the combination of whey protein and chitosan. The preparation process of the combination with whey protein and chitosan was selected as follows: wall material concentration 2.50%:1%, wall material ratio 3:1, pH 3.8, core-wall ratio 1:1, the selected homogenization time 3 min, and the efficiency 81.37 ± 0.29%. The results showed that the main volatile components in the microcapsules of Camellia oleifera seed oil were aldehydes, and the relative content of nonanal was 31.65%. The Fourier transform infrared results showed that this carrier of Camellia oleifera seed oil without changing its properties, and the thermogravimetric results showed that the microcapsules had better thermal stability. Moreover, the in vitro digestion results showed that the microcapsules could delay the digestion of Camellia oleifera oil in gastric juice. The camellia seed oil microcapsules in this study provide a new application for Camellia oleifera seed oil in many fields.

Channel Changes Choice: An Empirical Study About Omnichannel Demand Sensitivity to Fulfillment Lead Time

We examine a large transaction-level data set of an Italian omnichannel furniture retailer to study channel-specific effects of fulfillment lead time on demand. This omnichannel retailer sells the same products and has the same product fulfillment across three channels: showroom, online, and catalog. The showroom channel carries no inventory but allows customers to touch and feel the products. The online channel provides a website for consumers to browse and order the products. The catalog channel sends a product catalog to all the households in Italy, so they can place an order over the phone. We find that the showroom channel makes consumers less sensitive to fulfillment lead time than both online and catalog channels. In particular, a 10% increase in lead time (1.83 days from the sample mean of 18.26 days) causes a 0.29% reduction in the daily sales volume (approximately 29 units from the sample mean of 10,140 units per day) at the showroom, which is less than the reduction of 1.85% and 0.92% in the online and the catalog channels, respectively. This finding contradicts the common practical and theoretical assumption about homogeneous lead time sensitivity across channels. In addition, we find that niche products and experience goods accentuate the difference of lead time sensitivity between showroom and nonphysical channels. Through an online experiment, we show that higher product information precision, such as that provided in a showroom, can alleviate customers’ anxiety around product uncertainty, thus reducing lead time sensitivity and increasing purchase intent. We further build two analytical models to show the implications of our empirical results for showroom network design and inventory rationing decisions. Our study highlights the previously ignored fulfillment time sensitivity aspect of the physical store’s value. This paper was accepted by Vishal Gaur, operations management. Supplemental Material: The data files and online appendices are available at https://doi.org/10.1287/mnsc.2023.4839 .

An integrated Monte Carlo track-structure simulation framework for modeling inter and intra-track effects on homogenous chemistry

Objective. The TOPAS-nBio Monte Carlo track structure simulation code, a wrapper of Geant4-DNA, was extended for its use in pulsed and longtime homogeneous chemistry simulations using the Gillespie algorithm. Approach. Three different tests were used to assess the reliability of the implementation and its ability to accurately reproduce published experimental results: (1) a simple model with a known analytical solution, (2) the temporal evolution of chemical yields during the homogeneous chemistry stage, and (3) radiolysis simulations conducted in pure water with dissolved oxygen at concentrations ranging from 10 μM to 1 mM with [H2O2] yields calculated for 100 MeV protons at conventional and FLASH dose rates of 0.286 Gy s−1 and 500 Gy s−1, respectively. Simulated chemical yield results were compared closely with data calculated using the Kinetiscope software which also employs the Gillespie algorithm. Main results. Validation results in the third test agreed with experimental data of similar dose rates and oxygen concentrations within one standard deviation, with a maximum of 1% difference for both conventional and FLASH dose rates. In conclusion, the new implementation of TOPAS-nBio for the homogeneous long time chemistry simulation was capable of recreating the chemical evolution of the reactive intermediates that follow water radiolysis. Significance. Thus, TOPAS-nBio provides a reliable all-in-one chemistry simulation of the physical, physico-chemical, non-homogeneous, and homogeneous chemistry and could be of use for the study of FLASH dose rate effects on radiation chemistry.

Evaluation of the Survival of Lactobacillus fermentum K73 during the Production of High-Oleic Palm Oil Macroemulsion Powders Using Rotor-Stator Homogenizer and Spray-Drying Technique.

This study aimed to evaluate the survival of the probiotic Lactobacillus fermentum when it is encapsulated in powdered macroemulsions to develop a probiotic product with low water activity. For this purpose, the effect of the rotational speed of the rotor-stator and the spray-drying process was assessed on the microorganism survival and physical properties of probiotic high-oleic palm oil (HOPO) emulsions and powders. Two Box-Behnken experimental designs were carried out: in the first one, for the effect of the macro emulsification process, the numerical factors were the amount of HOPO, the velocity of the rotor-stator, and time, while the factors for the second one, the drying process, were the amount of HOPO, inoculum, and the inlet temperature. It was found that the droplet size (ADS) and polydispersity index (PdI) were influenced by HOPO concentration and time, ζ-potential by HOPO concentration and velocity, and creaming index (CI) by speed and time of homogenization. Additionally, HOPO concentration affected bacterial survival; the viability was between 78-99% after emulsion preparation and 83-107% after seven days. The spray-drying process showed a similar viable cell count before and after the drying process, a reduction between 0.04 and 0.8 Log10 CFUg-1; the moisture varied between 2.4% and 3.7%, values highly acceptable for probiotic products. We concluded that encapsulation of L. fermentum in powdered macroemulsions at the conditions studied is effective in obtaining a functional food from HOPO with optimal physical and probiotic properties according to national legislation (>106 CFU mL-1 or g-1).

Influence of homogenization degree on microstructure and mechanical properties for a novel wrought superalloy

The present work aims at investigating the impact of homogenization time on microstructure and mechanical properties of a Ni-based superalloy GH4151 during hot deformation. The results showed that dense dendrite structure remained after homogenization at 1200°C for 5 h, which was similar to as-cast microstructure. Higher flow stress and cracking in 5 h-homogenized material is attributed to the integral deformation of microstructure with greater resistance and less recrystallization. Furthermore, the decrease in dense dendrite structure with increasing homogenization time helped to promote dynamic recrystallization (DRX) during deformation at 1200°C for 12h and 36 h due to increasing nucleation position. When the homogenization time increased to 60h, increase of grain size makes dislocation gather within grain and resistance increase.

Effect of compositional homogenization on hot workability of Ni-based GH4061 superalloy

Complex solidification process, severe chemical segregation and large amounts of secondary phases with low melting point between dendrites deteriorate the hot workability of as-cast GH4061 superalloy. The effects of the homogenization temperature and time on the dendritic segregation, dissolution behavior of Laves phase with low melting point intermetallic phases and hot workability of the alloy were investigated using OM, SEM, EPMA and TEM. The results show that in the as-cast sample, severe compositional segregation is found among dendritic structures and the highest segregation coefficient of Nb is 2.435, followed by Ti of 1.346 and Mo of 1.200. After homogenization at 1160 °C for 20 h, the segregation among dendritic structures has been fully eliminated and the segregation coefficient of Nb declines to 1.098. Meanwhile, Laves and δ phases are mostly dissolved and no any localized grain boundary re-melting was observed. Increasing annealing temperature accelerates the speed of chemical homogenization and dissolution of intermetallic compounds. High-temperature mechanical properties testing results demonstrate that two-step homogenization treatment promotes the plasticity up to 1150 °C. Fracture analysis reveals that the dissolution of Laves and δ phases reduces the probability of crack initiation and fracture, resulting in a good hot workability.

EI Eridani: A star under the influence

Context. Homogeneous photometric time series spanning decades provide a unique opportunity to study the long-term cyclic behavior of active spotted stars such as our target EI Eridani. In addition, with ultraprecise space photometry data, it is possible to investigate the accompanying flare activity in detail. However, the rotation period of ≈2 days for EI Eri makes it impossible to achieve time-resolved surface images from a single ground-based observing site. Therefore, for this purpose, spectroscopic data from a multi-site observing campaign are needed. Aims. We use our photometric time series of more than 40 yr to analyze the long-term behavior of EI Eri. We investigate flare activity using photometric data obtained with the Transiting Exoplanet Survey Satellite (TESS). The MUlti-SIte Continuous Spectroscopy (MUSICOS) campaign in 1998 was designed to achieve high-resolution, multi-wavelength spectroscopic observations from many sites around the globe, which meant that uninterrupted phase coverage of EI Eri became available. We use these data to reconstruct successive surface-temperature maps of the star in order to study the changes of starspots on a very short timescale. Methods. We used long-term seasonal period analysis of our photometric time series to study changes in the rotational period. We also applied short-term Fourier-transform to look for activity cycle-like changes. We also studied the phase and frequency distribution of hand-selected flares. We applied our multi-line Doppler imaging code to reconstruct four consecutive Doppler images. These images were also used to measure surface differential rotation with our cross-correlation technique. In addition, we carried out tests to demonstrate how Doppler imaging is affected by the fact that the data came from several different instruments with different spectral resolutions. Results. Seasonal period analysis of the light curve reveals a smooth, significant change in period, possibly indicating the evolution of active latitudes. Temperature curves from B − V and V − I show slight differences, indicating the activity of EI Eri is spot dominated. Short-term Fourier transform reveals smoothly changing cycles of between 4.5 and 5.5 yr and of between 8.9 and 11.6 yr. The time-resolved spotted surface of EI Eri from Doppler imaging enabled us to follow the evolution of the different surface features. Cross-correlating the consecutive Doppler maps reveals surface shear of α = 0.036 ± 0.007. Our tests validate our approach and show that the surface-temperature distribution is adequately reconstructed by our method. The tests also indicate how accurately the cross-correlation method can reproduce the surface shear as a function of the spectral resolution.

Preparation and in vitro evaluation of hesperidin nanoparticles by antisolvent recrystallization in a double homogenate system.

Hesperidin nanoparticles (HNPs) were made for the first time employing an antisolvent recrystallization technique in a double homogenate system with positive and negative clockwise rotation in order to completely use the underutilized nutritional components in citrus peel. Dimethyl sulfoxide (DMSO), ethanol, and deionized water were used as the solvents and antisolvents in the hesperidin solution preparation. Hesperidin solution concentration of 60.26mg/mL, homogenization speed of 8257rpm, antisolvent-to-solvent volume ratio of 6.93mL/mL, and homogenization time of 3.15min were the ideal experimental conditions. HNPs have to be at least 72.24nm in size. The structures of the produced hesperidin samples and the raw hesperidin powder were identical, according to the findings of the FTIR, XRD, and TG characterization tests. The HNP sample had an in vitro absorption rate that was 5.63 and 4.23 times greater than that of the raw hesperidin powder, respectively. It was discovered that DMSO was more suited than ethanol for creating HNP particles. In the realms of dietary supplements, therapeutic applications, and health promotion, the HNPs produced by the ARDH technology would be a potential formulation on increasing uses for a wider range of nutraceuticals (synergistic).

Investigating the fast spectral diffusion of a quantum emitter in hBN using resonant excitation and photon correlations

The ability to identify and characterize homogeneous and inhomogeneous dephasing processes is crucial in solid-state quantum optics. In particular, spectral diffusion leading to line broadening is difficult to evidence when the associated timescale is shorter than the inverse of the photon detection rate. Here, we show that a combination of resonant laser excitation and second-order photon correlations allows to access such fast dynamics. The resonant laser drive converts spectral diffusion into intensity fluctuations, leaving a signature in the second-order coherence function $g^{(2)}(\tau)$ of the scattered light that can be characterized using two-photon coincidences -- which simultaneously provides the homogeneous dephasing time. We experimentally implement this method to investigate the fast spectral diffusion of a color center generated by an electron beam in the two-dimensional material hexagonal boron nitride. The $g^{(2)}(\tau)$ function of the quantum emitter measured over more than ten orders of magnitude of delay times, at various laser powers, establishes that the color center experiences spectral diffusion at a characteristic timescale of a few tens of microseconds, while emitting Fourier-limited single photons ($T_2/2T_1 \sim 1$) between spectral jumps.

Methodological Considerations for Assessing Automatic Brightness Control in Endoscopy: Experimental Study.

Endoscopy is a critical application that requires adaptable illumination to adjust to varying imaging conditions. Automatic brightness control (ABC) algorithms ensure optimal brightness throughout the image with rapid but smooth response and render the true colours of the biological tissue under examination. To achieve good image quality, high-quality ABC algorithms are necessary. In this study, we propose a three-assessment method approach for objectively evaluating ABC algorithms based on (1) image brightness and its homogeneity, (2) controller response and response time, and (3) colour rendition. We conducted an experimental study to assess the effectiveness of ABC algorithms in one commercial and two developmental endoscopy systems using the proposed methods. The results showed that the commercial system achieved good, homogeneous brightness within 0.4 s, and its damping ratio was 0.597, indicating a stable system, but its colour rendition was suboptimal. The developmental systems had control parameter values that resulted in either a sluggish response (over 1 s) or a fast (about 0.3 ms) but unstable response with damping ratios above 1, causing flickers. Our findings indicate that the interdependency among the proposed methods can establish tradeoffs in the overall ABC performance better than single-parameter approaches. The study establishes that comprehensive assessments using the proposed methods can contribute to designing new ABC algorithms and optimising already implemented ones for efficient performance in endoscopy systems.

Evaluation of a PAT-based in-line control system for a continuous spin freeze-drying process

Continuous spin freeze-drying provides a range of opportunities regarding the implementation of several in-line process analytical technologies (PAT) to control and optimize the freeze-drying process at the individual vial level. In this work, two methods were developed to (1) control the freezing phase by separately controlling the cooling and freezing rate and (2) control the drying phase by controlling the vial temperature (and hence the product temperature) to setpoint values and monitoring the residual moisture content. During the freezing phase, the vial temperature closely followed the decreasing setpoint temperature during the cooling phases, and the crystallization phase was reproducibly controlled by regulating the freezing rate. During both primary and secondary drying, vial temperature could be maintained on the setpoint temperature which resulted in an elegant cake structure after every run. By being able to accurately control the freezing rate and the vial temperature, a homogeneous drying time (SD = 0.07–0.09 h) between replicates was obtained. Applying a higher freezing rate significantly increased primary drying time. On the other hand, fast freezing rates increased the desorption rate. Finally, the residual moisture of the freeze-dried formulation could be monitored in-line with a high accuracy providing insight on the required length of the secondary drying phase.

Disparities in Pediatric Specialty Referral Scheduling and Completion

To estimate differences in scheduled and completed specialty referrals by race, ethnicity, language for care, and insurance type. We studied a retrospective cohort of 38334 specialty referrals to a large children's hospital between March 2019 and March 2021. We included referrals for patients with primary care clinics within 5 miles of the hospital. We examined whether the odds of and time to scheduled and completed referrals differed by patient sociodemographic characteristics. Of all referrals, 62% were scheduled and 54% were completed. Referral completion rates were lower for patients with Black race (45%), Native Hawaiian/Pacific Islander race (48%), Spanish language (49%), and public insurance (47%). Odds of scheduled and completed referral were lower for Asian (aOR scheduled: 0.94, [95% CI: 0.89, 0.99]; aOR completed: 0.92 [0.87, 0.97]), Black (aOR scheduled: 0.86 [0.79, 0.94]; aOR completed: 0.80 [0.73, 0.87]), and publicly insured patients (aOR scheduled: 0.71 [0.66, 0.75]; aOR completed: 0.70 [0.66, 0.75]). Time to scheduled and completed referral was longer for Black (adjusted hazard ratio [aHR] scheduled: 0.93 [0.88, 0.98]; aHR completed: 0.93 [0.87, 0.99]) and publicly insured patients (aHR scheduled: 0.85 [0.82, 0.88]; aHR completed: 0.84 [0.80, 0.87]) and families with a language other than English (aHR scheduled: 0.66 [0.62, 0.70]; aHR completed: 0.92 [0.86, 0.99]). Within a geographically homogenous pediatric population, the odds and time to scheduled and completed specialty referrals differed by sociodemographic characteristics, suggesting the effects of discrimination. To improve access equity, health care organizations need clear and consistent referral workflows and more comprehensive metrics for access.

Facile transformation of heavy oil residues into carbon composites used for high-performance supercapacitors

Asphaltene, an otherwise undesirable waste from the oil industry, was refined from heavy oil fractions and processed under different conditions to obtain carbonaceous materials with large surface area to be used in supercapacitors. Carbon electrode materials were successfully fabricated by a facile thermal process using melamine foam as template and KOH activation. The effect of different synthesis parameters on morphological and electrochemical performance is reported, namely, the weight ratio KOH:asphaltene, homogenization time, temperature and duration of thermal treatment. The materials were characterized by Raman, BET, SEM/EDS, and XPS; and their performance, in terms of specific capacitance and stability, was assessed by different electrochemical methodologies. Results show that an optimized material, using specific capacitance and active material recovery as optimization targets, was obtained by using a KOH: asphaltene weight ratio of (3:1), homogenization time of 1 h and thermal treatment at 700°C for 0.5 h. This material had a specific energy of 8.6 W h kg−1, specific power of 645 W kg−1 and a specific capacitance of 112 F g−1 at 0.4 A g−1 current density.

Formulation of Nano-sized dispersion from Calendula Officinalis: A Natural gateway to preparation of a Hair Dye

Hair dyes have been used to cover gray hair or to give an appealing look. In the present study, the extract of Calendula Officinalis was used in preparing a hair dye. This represents a natural gateway in development of hair dye to avoid damage caused by synthetic dyes. The yellow coloring principle of the extract, Calendulin, was converted into nano-sized formula ensuring hair fiber penetration. Nine formulae were prepared by solvent evaporation technique, based on a 32 factorial design using Design Expert® program, independent variables being: speed and time of homogenization; three levels: low, medium and high. Polyvinyl alcohol (0.5% w/v) was used as stabilizing agent. Formulae were evaluated by determination of Zeta size, potential and polydispersity index. Response surface modeling enabled choosing the optimal formula (least particle size, polydispersity index and highest zeta potential), which was evaluated by transmission electron microscopy and dyeing effect as a gel containing 0.5% Carboxymethyl cellulose. F7, produced by operating the homogenizer at 26000rpm for 10 minutes proved to be optimal which succeeded to dye white hair and lighten up the black hair as evidenced by optical microscope images. Hence it was recommended to use F7 in covering the white hair.