Commercial Grade Research Articles

Prediction of Thermal Properties and Reliability Testing of Binary Eutectic Mixture of Polyethylene Glycol 2000 and 10000 as Phase Change Materials

AbstractThis experimental investigation presents the two major aspects of thermal energy storage materials. One is development of eutectic mixtures of polyethylene glycols (PEGs) and another is thermal reliability of them. The commercial grade PEGs with molecular mass 2000 and 10000 were mixed in different mass fractions via facile incorporation method for preparing the eutectic mixtures. The thermal energy storage capacity was measured by using differential scanning calorimeter (DSC) and Fourier transform and infrared spectroscopy (FT‐IR) was adopted to analyse the variation in chemical compositions of eutectics. The eutectics were prepared in the step of 10% mass fraction and characterization show that the mixture of 20% PEG 2000 and 80% PEG 10000 possess the maximum latent heat of fusion, which is 185 kJ/kg. The prepared eutectic mixture was also tested for its durability by in‐house designed thermal cycling tester. The results revealed that this eutectic is able to retain its thermal and chemical properties even after 1500 melting and freezing cycles. The findings of this study show that the prepared binary eutectics are able to be used as potential candidates for passive solar thermal management purposes.

Characterization of transparent p-type Cu:ZnS thin films grown by spray pyrolysis technique

Commercial grade p-type transparent conducting Cu doped ZnS thin films with high optical transparency as well as high hole conductivity were grown by industrially beneficial spray pyrolysis method. Pristine ZnS being with wide band gap and high transparency has limited application in optoelectronics due to its low n-type electrical conductivity. To overcome these limitations, ZnS was grown with copper as dopant in +1 state, creating holes to form p-type material. Structural and various spectroscopic studies were conducted to confirm the incorporation of copper and to investigate its chemical state. Analysis has confirmed the formation of Cu:ZnS (CZS) thin films and revealed the formation of Cu:ZnO (CZO) phase along with CuxS related phases in minor fraction. Films with Cu dopant concentration 5 at.% and above have exhibited p-type conductivity. Films with 15 at.% Cu dopant have shown higher electrical conductivity (about 1.37 Scm−1) by retaining about 64% optical transparency at the mid of visible range.

Impact of Some Natural Extracts and Nutrients on Different Growth Measurements of Washington Navel Orange Transplants

This study was conducted throughout the two successive seasons of 2018 and 2019 at Fruit Nursery of Horticulture Department, Faculty of Agriculture at Moshtohor, Benha University Qalubia Governorate, Egypt., to study the impact of some natural treatments, i.e., Algae, Yeast extract, Moringa leaves extract and nutrients as compound that containing both macro (N, P, K) and micro (Fe, Zn, Mn, Fe, Cu) elements and compound containing macro and microelements and some growth regulators. These materials (natural extracts and nutrients) were applied as a foliar spray at different concentrations to evaluate their effect on different growth parameters of one year old Washington navel orange transplants budded on sour orange rootstock. These materials were applied once in a month started from the last week in April to the last week in September .as per the treatment as: Blue-green algae extract (1, 2 and 3 ml/L), Yeast extract (10, 20 and 30 ml/L), Moringa leaves extract (2.5, 5 and 7.5 g/L). Nitro active 20: 20: 20 (commercial grade) (0.5, 1 and 1.5 g/L) and Estima green (commercial grade) (0.5, 1 and 1.5 g/L). The result indicated that the application of Blue-green algae at 3 ml/L and Estima green at 0.5g/L cause a significant increase in the different growth parameters under this study i.e., length, diameter, number of leaves, leaf area, fresh and dry weights. On the contrary, the least values of the abovementioned parameters were usually in concomitant to T1 - control (water sprayed) which ranked statistically last during both seasons of study.

Primary Frequency Support Through North American Continental HVDC Interconnections With VSC-MTDC Systems

This paper proposes a frequency control strategy for voltage source converter based multi-terminal HVDC systems (VSC-MTDC) to facilitate the exchange of primary frequency reserves among asynchronous AC systems, thus providing frequency support from each AC system to the others. The proposed frequency control utilizes a reference signal calculated from global measurements which reflects the overall frequency dynamics of all connected asynchronous AC systems. The proposed control outperforms the traditional frequency droop scheme by reducing impact on the DC voltage profile and improving frequency nadir. The performance of the designed frequency control with different DC voltage droop controls is evaluated. The adaptation of the proposed frequency control for converter outages is analyzed. The robustness of the proposed control to communication latency and the sensitivity of frequency support to power limits are also investigated. The VSC-MTDC model and the proposed control are implemented in the commercial grade software PSS/E and thus is suitable to study large-scale realistic systems and can be incorporated into the power system planning process at utilities and ISOs. The effectiveness of the proposed control is illustrated on a developed AC-MTDC test system and also on a large-scale realistic model combining the North American Western Interconnection (WI) and Eastern Interconnection (EI) with continental HVDC interconnections.

Reduction of surface oxide layers on water-atomized iron and steel powder in hydrogen: Effect of alloying elements and initial powder state

The reduction of surface oxide layers covering commercial water-atomized iron and steel powder grades have been investigated using model thermogravimetric reduction cycles in hydrogen. The influences of powder composition and initial condition on the oxide reduction were studied for three powder grades and compared to Fe2O3. Isothermal and dynamic measurements were conducted to assess the reduction progress and kinetic analyses were then used to calculate the apparent activation energies of reduction. Chromium-alloyed powder showed significantly lower activation energies compared to iron powder and Fe2O3, likely originating from the presence of Cr oxide in the oxide layer. The reduction was also found to be strongly affected by the initial state of the oxide layer which reflects the powder production. Surface analysis by X-ray photoelectron spectroscopy (XPS) showed a progressive increase in Cr with gradual reduction of the oxide layer, indicating its presence and possible involvement in the oxide reduction.

Reprocessed Uranium Hexafluoride Purification from 232,234,236U in Pentaflow Gas-Centrifuge Cascades

A computational experiment was performed to purify reprocessed uranium hexafluoride from 232,234,236U in an additional product flow of cascades with a specified number of gas centrifuges in stages. The method used in the calculations takes into account the dependence of the separation coefficients of gas centrifuges on their feed flow and flow division factor. A cascade scheme for purification with simultaneous production of low-enrichment uranium from natural uranium in the main product is investigated. The cascade has to feed flows with regenerated natural-uranium hexafluoride, two product flows, and one waste flow. The cascade parameters that increase the purification efficiency are determined. It is shown that uranium hexafluoride in the products of the cascade satisfies the ASTM C996–15 international specifications established for low-enrichment commercial grading.

Dielectric and piezoelectric perfomance of lead-free ceramics of boron sodium gadolinate niobate at morphotropic phase boundary

New lead-free piezoceramic nanocomposites of Boron Sodium Gadolinium Niobate (BNGN), with general formula (1[Formula: see text][Formula: see text][Formula: see text][Formula: see text][Formula: see text][Formula: see text][Formula: see text]NbO3, exhibiting a Morphotropic Phase Boundary (MPB), have been synthesized following hydrothermal method followed by solid state sintering. The occurrence of MPB at the composition with [Formula: see text], at which rhombohedral and monoclinic phases are found to coexist, has been confirmed using powder XRD. This accounts for the occurrence of large remnant polarization when the sintered ceramic pellets are subjected to electric poling at 2KV/mm. Uniform microstructure of various compositions is confirmed by SEM imaging. Dielectric and piezoelectric properties of the samples are found to be comparable to those of commercial grade PZT. At the MPB, the [Formula: see text] coefficient is found to be 556 pC/N, which is close to that of commercial grade PZT, which makes BNGN a promising material to substitute lead containing PZT in the near future.

Material Contact and Environmental Effects on Vitamin A Fortified Vegetable Frying Oil

Observations about the impact of environmental parameters and time, on fortified vegetable oil, using typical commercial grade linear low density polyethylene (LLDPE) packaging during typical shelf-life conditions, are minimal. We tested the long-term (12 months) impact of temperature and illuminance (light: 100 to 150 lux and darkness <1 lux) on refined bleached deodorized palm olein (RBDPOL), fortified with vitamin A, and without antioxidant. Results showed degradation of fortified RBDPOL with 70 ppm vitamin A was approximately 19% at 18-22oC in Light, 18% at 18-22oC in Darkness, 38% at 32-33oC in light and 24% 32-33oC in darkness. A similar trend was observed at 45 ppm vitamin A. Exposure to both heat and light impacted vitamin A degradation, but was primarily attributed to prolonged exposure at elevated temperature, irrespective of the packaging material. This short study validates extensive research by Silalahi et al., (2017), doi:10.1111/ijfs.13462 on the impact of environmental effects of fortified vegetable frying oil, during extensive storage life periods.

Redispersion of cryoaggregated gold nanoparticle by means of laser irradiation and effect on biological interactions

Agglomeration/aggregation is an indispensable phenomenon observed by different nanoparticles. In the present study, commercial grade (50 nm) and chemically synthesized (40 nm) gold nanoparticles (AuNPs) were aggregated at sub-zero temperatures, followed by disruption of the AuNP aggregates via nanosecond laser-ablation and subsequent effect on biological interactions. AuNPs were characterized pre/post laser-ablation via UV-visible spectroscopy, transmission electron microscopy, atomic force microscopy, etc. The process of freezing (aggregation) and laser-ablation (dispersion) was performed multiple times, in order to compare the yield of nanoparticles after each cycle of laser-ablation. Further, AuNPs pre/post laser-ablation were assessed for cytotoxicity, protein-corona formation, and cell-uptake by in vitro studies using RAW264.7, Caco-2 and Neuro-2 a cell lines. Aggregates for both the types of AuNPs displayed fragmentation following first cycle of laser-ablation. In addition, AuNPs obtained after fragmentation of the aggregates showed reduction in diameter and reshaping, as compared to native AuNPs. The size and shape of the nanoparticles after second and third cycle of laser-ablation was same as that obtained after first cycle of ablation. Both laser-ablated and native AuNPs showed similar effects on viability of RAW 264.7 and Caco-2 cells, after 24 h and 48 h of exposure. Cell uptake of native and laser-ablated AuNPs was observed to be a size dependent phenomenon. Present findings showed that nanosecond laser ablation of cryoaggregated AuNPs lead to changes in the physical properties of AuNPs post ablation like size and shape, however, biological interaction with cells remained same. This work is first report on biological interactions of AuNPs generated via laser-ablation of cryoaggregated AuNPs.

Preparation of black titanium monoxide nanoparticles and their potential in electromagnetic wave absorption

In this work, black titanium monoxide (TiO) nanoparticles were synthesized by hydrogen assisted magnesium thermal reduction method from nanotube titanic acid (NTA) and their electromagnetic properties were investigated. The black TiO nanoparticles exhibited the optimal reflection loss of −37.7 dB at a thin absorbance layer of 1.2 mm in thickness, which showing a promising candidate in electromagnetic wave absorbing (EA). To explore the mechanism of EA, TiO nanoparticles prepared from the other two initiators (commercial grade TiO and P25 titanium dioxide) was used as a comparison. The results show that the crystalline structure and microscopic defects, which arouse from the formation of TiO in the hydrogen assisted process, affect the electromagnetic performance of Ti-O binary system significantly in addition to their intrinsic effects. We hope this study help to open a new way for the designing of high-performance EA materials.

Structural, mechanical and tribological investigations of CNT-316 stainless steel nanocomposites processed via spark plasma sintering

In this work, carbon nanotube (CNT) reinforced 316 L stainless steel (SS) composites were studied for the impact of CNT content on their microstructural, mechanical and tribological behaviour. Carbon nanotube-SS composites were fabricated via spark plasma sintering process at a sintering temperature of 800 °C. The tribological behaviour for pristine and 0.2, 0.5, 1.0, and 2.0 wt% CNT loaded samples was studied by a ball-on-disc tribometer under a normal load of 10 N at 28 °C and 300 °C. Microstructural studies showed grain refinement with the addition of CNT and hence enhancement in hardness and yield strength. The friction coefficients for high temperature tests were found to be lesser than that of room temperature values. Decrease in friction coefficient at high temperature tribotests compared to low temperature case could be attributed to the lubrication effect coming from local melting and CNTs. The lubrication of CNTs coming from its unique shape, aspect ratio, and flexibility. The wear rate was found to decrease with increasing CNT concentration in both cases. For the 2 wt% CNT case, the wear volume at 28 °C and 300 °C were nearly the same due to the lubrication effect. About 25% and 90% reduction in wear volume was observed for 2 wt% CNT sample at room temperature and 300 °C, respectively, when compared to their pristine counterpart. The composited samples showed increased resistance to wear than the pristine and commercial grade at both temperatures. A systematic study on the morphology, structure, hardness, yield strength, elemental composition, and tribology of the composites to understand the structure-property correlation of CNT-steel composite is presented in detail.

Enhancement of aqueous solubility and extraction of lauric acid using hydrotropes and its interaction studies by COSMO-RS model

In this study, COnductor like Screening MOdel for Real Solvents was used to analyze the ability of hydrogen bond donor, hydrogen bond acceptor and electron affinity of all the studied species such as water, lauric acid (LA), sodium benzoate (SB), sodium salicylate (SS), nicotinamide (NI), and urea (UA). Further, the different hydrotropes solutions were prepared with different concentrations (0–3.0 mol/L) in order to analyze the solubility of lauric acid at different temperatures (303–313 K). Subsequently, hydrotropes based extraction of lauric acid from cold press coconut oil (CPCO) and commercial-grade edible coconut oil (CGECO) was conducted at 313 K and 0.1 MPa. GC–MS analysis has been carried out on cold press coconut oil, commercial grade edible coconut oil and hydrotropically extracted samples to characterize the different fatty acid compounds present in it. It was observed that the sodium benzoate hydrotrope solution extracted samples has lauric acid as a significant component in the GC-MS spectra when compared to the extracted samples of sodium salicylate hydrotrope solution.

Design and Characterization of a Novel Fermented Beverage from Lentil Grains.

The experimental activities carried out in this study aimed at designing a lentil-based beverage rich in soluble and digestible proteins. In order to extract soluble proteins, lentil grains were soaked in water overnight, blended, treated with proteolytic enzymes and fermented with Lactobacillus strains. Protein enzymatic hydrolysis, carried out with four commercial food grade enzyme preparations, showed that bromelin, at the enzyme to substrate ratio of 10%, was the best solution to produce this novel beverage. Even though the seven Lactobacillus strains were all able to ferment aqueous extract within 24 h, L. acidophilus ATCC 4356, L. fermentum DSM 20052 and L. paracasei subsp. paracasei DSM 20312 showed the highest growth rate and the lowest pH values. In fermented lentil-based beverages, the antinutritional factor phytic acid decreased up to 30%, similarly, the highest reduction in raffinose oligosaccharides content reached about 12% the initial concentration. It is worthy of note that the viable density of all strains remained higher than 7 log cfu/mL after 28 days of cold storage. The results here reported show for the first time the possibility to obtain a probiotic lentil-based beverage rich in soluble proteins, peptides and amino acids with low content in main antinutritional factors.

Agreement Between Fitbit And Actigraph Estimates Of Physical Activity In Young Children

Commercial wearables are used to track physical activity (PA) levels in children and as tools for increasing PA participation in youth. However, few studies have examined the agreement between commercial and research grade devices in assessing PA in children. PURPOSE: To compare estimates from a wrist-worn Fitbit Flex 2 to a waist-worn Actigraph GT9X Link in elementary school children. METHODS: Forty children aged 6-10 years wore a Fitbit Flex 2 (on non-dominant wrist) and an Actigraph GT9X Link (on waist) for up to two weeks while school was in session. Children were instructed to wear the Fitbit continuously and to wear the Actigraph during all waking hours. Parents were given wear reminders via text each morning. For each device, an adapted Choi algorithm was used to flag non-wear periods (defined as ≥90 minutes of continuous 0 step values). Steps and intensity-specific estimates of daily PA from each device were averaged across time periods when both devices were worn simultaneously, and estimates were compared using days with 10+ h of concordant wear and using all available data. RESULTS: Across 91 days with concordant device wear of 10+ h, Fitbit estimates were 25% higher for steps (Mean±SD = 10318±3846 steps) and 44% higher for vigorous intensity PA (16.2±22.1 min) compared to the Actigraph GT9X Link (8260+3614 steps; 11.3±15.9 min). In contrast, Fitbit estimates of moderate intensity PA (26.8±21.1 min) were 20% lower than Actigraph estimates (33.3±24.3 min). Pearson correlations between device estimates were higher for steps (r=0.62) than for moderate (r=0.55) or vigorous (r=0.28) intensity PA. Similar patterns were observed when all available concordant data were analyzed (n=377 days), with the Fitbit recording 20% more steps, 28% less moderate PA, and 36% more vigorous PA than the Actigraph. CONCLUSIONS: Wrist-worn consumer wearables may produce higher estimates of steps and vigorous intensity PA, and lower estimates of moderate intensity PA, in elementary school children. Absent additional evidence, consumers and researchers should be cautious when using wrist-worn consumer devices to assess absolute levels of PA in youth. Supported by a grant from NHLBI (R01HL135359).

An Exploratory Comparative Study of Fabricated Silica – Aluminium Metal Matrix Composites with Casted Aluminium-Silicon Alloys

Different commercial grades of aluminium have been used in which LM6 grade is most available. An attempt has taken towards developing Aluminium-Silicon Alloys (Al-Si alloys) via conventional casting and investment casting separately. Parallel effort has made to develop silica – aluminium metal matrix composites using both crystalline and non-crystalline form of silica separately as reinforcement. Comparative study has carried out based on different physical and mechanical properties of developed products.

Isothermal crystallization of PLA: Nucleation density and growth rates of α and α' phases

AbstractFrom a technological point of view, poly(lactic acid) (PLA) is one of the most important polymers produced from renewable sources, due to its versatility, relatively acceptable processability, and low cost. However, a significant limitation exists in its slow crystallization kinetics, which results in amorphous products having low mechanical properties and thermal resistance. For this reason, quantitative knowledge of the phenomenon of crystallization kinetics is fundamental. In this work, the crystallization kinetics in quiescent conditions of a commercial grade of PLA was analyzed in terms of nucleation and growth rates by direct morphological observations at different crystallization temperatures (Tc) and by calorimetric analysis in isothermal and non‐isothermal conditions. The optical analysis showed a spherulitic morphology with radial growth of the lamellae. The analysis of the growth rate evidenced the α/α'‐crystals polymorphism with a transition temperature of ~120°C. Based on experimental observation, the crystallization kinetics of the two crystalline phases were assessed.

Recovery of Metals from Dry Shot Blast Waste Generated in the Stainless-Steel Production Process

Dry shot blast generated during stainless steel production contains high content of valued metals such as iron chromium and nickel. These metals are in the form of oxides and it can be used as a raw material in iron and steel. This work aims to study the feasibility of metals recovery from dry shot blast by smelting reduction process. Smelting reduction of dry shot blast by using coking coal as reductant was conducted in an induction furnace. The effect of metallurgical parameters e.g. stoichiometry ratio of reductant per oxygen containing in dry shot blast, CaO/SiO2 of slag forming and CaF2 in slag, on %recovery of metal product was investigated. The results based on this study showed that the weight of metal product increases with increased the amount of coke to about 1.5 of stoichiometric molar ratio. Increasing of coke above this amount leads to decrease %recovery of metal product. Moreover, the weight of metal product is increased when the ratio of CaO/SiO2 in slag decreased from 2 to 1. The chemical composition of the metal product is in the range of commercial grade and it can be used as raw materials to produce steel and cast iron alloy.Dry shot blast generated during stainless steel production contains high content of valued metals such as iron chromium and nickel. These metals are in the form of oxides and it can be used as a raw material in iron and steel. This work aims to study the feasibility of metals recovery from dry shot blast by smelting reduction process. Smelting reduction of dry shot blast by using coking coal as reductant was conducted in an induction furnace. The effect of metallurgical parameters e.g. stoichiometry ratio of reductant per oxygen containing in dry shot blast, CaO/SiO2 of slag forming and CaF2 in slag, on %recovery of metal product was investigated. The results based on this study showed that the weight of metal product increases with increased the amount of coke to about 1.5 of stoichiometric molar ratio. Increasing of coke above this amount leads to decrease %recovery of metal product. Moreover, the weight of metal product is increased when the ratio of CaO/SiO2 in slag decreased from 2 to 1. The chemical composition of the metal product is in the range of commercial grade and it can be used as raw materials to produce steel and cast iron alloy.

Properties of non-woven polylactic acid fibers prepared by the rotational jet spinning method

The preparation of non-woven polylactic acid (PLA) fibers was carried out by the rotational jet spinning method. The polymers were melted in a heat chamber and centrifuged with a high speed to obtain the fibers with the high productivity. The viscosity of polymers was an important factor for the quality and quantity of the non-woven fiber. In this work, a commercial grade and synthesized PLA were used to prepare the non-woven fiber. The non-woven PLA fibers were produced at different temperatures of 190–230 °C with rotational speed between 650 and 2800 rpm. The morphology of non-woven PLA was investigated by scanning electron microscopy. The effect of temperature was investigated by thermogravimetric analysis (TGA). The non-woven PLA had a smooth surface along the fibers. The result showed that as the temperature or rotational speed increased, the fiber diameter was decreased. The fiber diameters of PLA 3052D, L130, and synthesized PLA (at 650 rpm) decreased to 40%, 40%, and 24%, respectively, when increasing the temperature. The high temperature in the process led to generate the beads. The fiber diameter of PLA 3052D, L130, and synthesized PLA (at 190 °C) decreased to 66%, 23%, and 56%, respectively, with the higher rotational speed. Tonset of TGA showed that the thermal degradation of PLA fibers was reduced compared with PLA resin, but it was still considered to be insignificant after spinning. The wettability of the samples was determined by the mean of the water evaporation. The results showed that the weight of the water in the sample decreased rapidly compared with control cotton, indicating more hydrophobic nature of the fibers obtained at the high rotational speed and temperature.

The Analysis of 3D Printer Dust for Forensic Applications,.

3D printers are becoming increasingly efficient and economical, and thus more widespread and easily accessible to consumers and businesses. They have been used to print nefarious objects such as guns and suppressors. Previous research has documented the release of dust particles during the printing process; however, little has been written about the morphology and chemical features that define the dust emitted by these printers. This study was undertaken to recover, analyze, and identify the dust produced during the printing process in the context of forensic trace evidence analysis. Samples were collected from a variety of 3D fused deposition modeler printers, representing both consumer and commercial grade models. This work focused on printers that use thermoplastic filaments composed of acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), two of the most commonly used filament polymers. Swabs were used to collect dust within the printer chamber and then processed to isolate the dust particles. Particles produced from ABS filaments are most easily recognized via light microscopy through a combination of color, morphology, and fluorescence. The composition of these particles can be confirmed through analysis by either FTIR or Raman microspectroscopy. These methods can also be used to identify ABS fillers and pigments within the printer dust particles. In contrast, dust from PLA printers consistently contained finer, submicron-sized particles that could be observed by field emission scanning electron microscopy. Because the size of the particles precludes their identification using vibrational spectroscopy methods, pyrolysis-GC-MS was used to confirm the presence of PLA.

Fast testing of ambient temperature pitting corrosion in type 2205 duplex stainless steel by bipolar electrochemistry experiments

Commercial grade type 2205 duplex stainless steel is resistant to localised corrosion at room temperature. With the application of bipolar electrochemistry, pitting and crevice corrosion can be probed at room temperature, with corrosion pits nucleated in 0.1 M HCl within 15 s of exposure. The evolution of localised corrosion kinetics as a function of applied electrochemical potential is discussed. Pit nucleation occurred at the interface between ferrite and austenite, growing into the ferrite phase. Pits with lacy covers formed via selective dissolution of the ferrite.