Commercial Grade Research Articles

Multi response optimization of injection moulding process to reduce sink marks and cycle time

In the rapidly growing field of technology, there is a demand for consumer goods made of plastic. To meet needs of customer, plastic products are made in different ways. There are different plastic manufacturing process. Numerous plastic manufacturing process are thereInjection molding is involves injecting molten material into a mold and allowing it to take on the shape of the mold.There are wide ranges of products such as plastic chairs, Computer cabinet etc. are manufactured with the help of smaller and more complex profiles. Due to lack of dimensional accuracy these complex profile produces defects inside the mold. Current study provides insights into transparent thermoplastic Polypropylene products. Five plastic injection molding variable criteria are considered for reducing the depth of sink mark in injection molding for commercial grade transparent thermoplastic (Polypropylene). Melting temperature (8C), mold temperature (8C), packing time (seconds), ratio of ribs to walls (%) and rib to gate distance (mm). According to Taguchi's design L27 experiments are performed and factors are optimized using the Taguchi based utility concept for multi criteria problems. The sink mark's depth on the part's surfaceis considered as quality of product and cycle time is considered as the productivity of product. It is the one of the best techniques, which can maintain the equilibrium between two.

Thousand shades of gray – The role of imaging display in diagnosis of occult scaphoid fractures – A pilot study

IntroductionMost hospitals and clinics utilize commercial grade displays for viewing wrist radiographs. There is no evidence regarding the role of the imaging display used to evaluate the radiographs. The aim of this study was to compare the rates of scaphoid fracture diagnosis by commercial grade and medical grade displays. MethodsWrist radiographs of patients that had clinical signs of scaphoid fracture without findings on plain radiography (suspected scaphoid fractures) were retrospectively collected from ER department and interpreted for radiographic signs of fracture by four orthopedics seniors commercial grade and medical grade displays. The difference in fracture diagnosis rates were studied. Inter- and intra-observer variability were also studied. ResultsStudy population comprised of 175 high quality wrist radiographs were interpreted. Mean 48.25 (27%) scaphoid fractures were observed on commercial grade display compared to 66 (38.2%) on medical grade display (p = 0.076). The total inter-observer agreement could be defined as a moderate agreement (κ = 0.527, Accuracy = 0.77). Total agreement between all observers were observed in 86 (49.1%) cases compared to 89 (50.9%) cases when reviewing X-rays on commercial and medical displays, respectively. DiscussionThe scaphoid fracture detection rate on medical grade display was not statistically higher compared to non-medical grade displays, but we did find a tendency toward medical grade display. We found that in a substantial number of cases, our observers recognize signs of fracture that were initially evaluated as "suspected fracture" by the ER physicians. As a pilot study, we found evidence that support the need for a prospective study designed to compare the observations to a gold standard modality, such as MRI. We believe utilizing medical grade displays can increase the rate of diagnosis in cases of clinically suspected scaphoid fractures and better manage the clinical scenario of a suspected scaphoid fracture.

Optimization of Multi-Layer Data Recording and Reading in an Optical Disc

Storage capacity of a conventional optical disc can be enhanced significantly by recording data within the three-dimensional volume. However, spherical aberrations and light-scattering limit the number of layers that can be efficiently recorded and retrieved. In this paper, we show that by optimizing the multi-layer data recording and reading parameters, the number of fabricated layers could be tripled to 60 in commercial grade poly-methyl-methacrylate polycarbonate and reduce the read laser power by a factor of 7 by the 20th layer. Influence of spherical aberration on write laser spot size was studied by using vector diffraction theory and compared with experimental values obtained by monitoring the threshold energy of the write laser with depth. Scattering losses of the read laser were studied by simulating the propagation of light through multi-layered micro-structured material. The main advantage of our technique is its practical implementation, as it refrains from the use of index-matching liquids and specialized optics during the read–write process.

Crystallization kinetics of melt-mixed 3D hierarchical graphene/polypropylene nanocomposites at processing-relevant cooling rates

Knowledge of the solidification behaviour of isotactic polypropylene (iPP) composites with reduced graphene oxide nanoplatelets is key to open the possibility to widespread use of these high performing nanocomposites. The crystallization behaviour of these systems, with filler content in the range of 0.2–3.5 wt% has been investigated by differential scanning calorimetry (up to 100 °C/min) and ex-situ structural and morphological characterization of samples prepared at processing-relevant cooling conditions (up to 2000 °C/s). Compared to the self-nucleated neat iPP, the nucleation efficiency was estimated to vary from 44 to 93% when increasing the filler content. Such a high nucleating efficiency has not been reported yet for a nanocomposite with iPP matrix. This result is due to the very good dispersion of the filler in these melt-mixed graphene-based polypropylene systems. The nucleation ability of the graphene filler does not reach a saturation in the concentration range studied. The gap between laboratory and industrial cooling rate scale is here reduced thanks to the information achieved from the fast-cooling experiments. By varying the filler amount in the investigated range, a significant shift of the cooling rate window in which the transition from α-to mesophase dominated crystallization takes place was detected. Notably, with 3.5 wt% graphene platelets, α-phase crystals are predominantly present in the material even after quenching at 1000 °C/s, similar to highly nucleated commercial iPP grades.

Shrimp shell waste-derived astaxanthin in synergistic combination with its commercial variant augments gonadal maturation and upregulates vitellogenin gene expression of discus (Symphysodon aequifasciatus)

A study was performed to evaluate the efficacy of shrimp shell meal derived natural astaxanthin (SSM), supplemented with its commercial variant on gonadal maturation and vitellogenin gene (Vtg.) expression in reproductively active adults of the high-value ornamental cichlid discus (Symphysodon aequifasciatus) reared under captivity. Four isonitrogenous (50% crude protein), isolipidic (9% ether extract), and isocaloric (400 kcal digestible energy/100 g) experimental diets viz. control (commercial grade astaxanthin, without SSM), T1 (15% SSM + commercial astaxanthin), T2 (20% SSM + commercial astaxanthin), T3 (25% SSM + commercial astaxanthin) were prepared and fed to satiation level twice daily for the entire experimental period of 90 days. Results revealed significant (p < 0.05) linear, quadratic, and overall trends, wherein GSI increased with an increase in the proportion of SSM in the diet, with higher GSI recorded in T2 and T3 treatment groups (testis and ovary, respectively), which were significantly (p < 0.05) different from other groups. The overall linear and quadratic trends of HSI differed significantly (p < 0.05) with the variability in proportions of natural and commercial astaxanthin combinations and were found highest in the T2 treatment group. Cholesterol, FSH, LH, 11-KT, 17β- Estradiol, and 17α-20β DHP levels increased with an increasing proportion of natural astaxanthin and recorded the highest values in the treatment T2 with an overall significant linear and quadratic trend as compared to other treatments. Most of the oocytes of T2 and T3 groups were in the vitellogenic phase, i.e., primary, secondary, and tertiary yolk stages. More spermatids were visible in testicular tubules in T2, followed by T3 and T1. The abundance of Vtg. mRNA was significantly (p < 0.05) evident in T2, followed by T1, then in control. Further increase in SSM inclusion caused a downregulation in the expression of this gene in the T3 group. The dietary combination of SSM @200 g/kg diet with its synthetic/commercial variant exhibited optimum performance at combination levels of 77.5 and 22.5 mg/kg, respectively, evidenced in terms of changes in steroid hormone profiles, gonadal maturation and vitellogenin gene expression in comparison to the control, which contained the dietary synthetic/commercial variant of astaxanthin alone. These inferences are presumably a milestone in the captive broodstock development of this high-value ornamental cichlid, S. aequifasciatus, with an added advantage of cost-effectiveness. The study would help the utilisation of economically important bio-waste in combination with commercial variants for effective value addition in the ornamental fish feed industry.

Effect of Whey Protein Purity on the Characteristics of Algae Oil-Loaded Encapsulates Obtained by Electrospraying Assisted by Pressurized Gas.

In this paper, the effect of protein purity in three different whey protein grades on the characteristics of algae oil encapsulates obtained via room-temperature electrospraying assisted by pressurized gas (EAPG) encapsulation process was studied. Three different commercial grades of whey protein purity were evaluated, namely 35, 80, and 90 wt.%. Oil nanodroplets with an average size of 600 nm were homogeneously entrapped into whey protein microparticles 3 µm in size. However, the sphericity and the surface smoothness of the microparticles increased by increasing the protein purity in the grades of whey protein studied. The porosity of the microparticles was also dependent on protein purity as determined by nitrogen adsorption–desorption isotherms, being smaller for larger contents of protein. Interestingly, the lowest extractable oil was obtained with WP35, probably due to the high content of lactose. The peroxide values confirmed the superior protective effect of the protein, obtaining the smallest peroxide value for WP90, a result that is consistent with its reduced porosity and with its lower permeability to oxygen, as confirmed by the fluorescence decay–oxygen consumption method. The accelerated stability assay against oxidation confirmed the higher protection of the WP80 and WP90. In addition, the increased content in protein implied a higher thermal stability according to the thermogravimetric analysis. These results further confirm the importance of the adequate selection of the composition of wall materials together with the encapsulation method.

Thermal optimization of secondary cooling systems in the continuous steel casting process

A new process design methodology for the cooling system in the continuous steel casting process is introduced. It is based on a semi-empirical approach for choosing the primary cooling zone design parameters and using an optimization-based method to decide on the design parameters corresponding to the secondary cooling zone. The heat flux through the secondary cooling zone is the design parameter in the latter case. Unlike former studies that considered a misfit temperature function as the objective function, it is defined here as the square of the temperature field penalized with the Niyama’s criterion infeasibility to ensure the production of microporosity-free strands. This way, no information about the target temperature field is required in advance. The corresponding heat transfer problem is coupled to CALPHAD to consider commercial steel grades straightforwardly. An efficient gradient-based optimization algorithm is employed to find the optimal values of design parameters. Then, this algorithm is employed in an actual process design problem corresponding to the continuous slab casting of a commercial steel grade. A post-processing approach is suggested to convert the results of numerical optimization to industrially relevant machine parameters, and then they are exploited in practice in the foundry plant. While the optimization problem is only constrained to avoid solidification-induced defects, it produces sound and crack-free strands. Moreover, comparing numerical results to actual surface temperature measurements reveals more petite than a six percent discrepancy between the simulation and experiment. These observations illustrate the feasibility of the presented design methodology as the initial step in deciding on the cooling system parameters in this process.

An innovative approach to develop self‐healing materials from commercial tire‐grade elastomers

In the present work, a solid state environment-friendly methodology has been adopted to produce self-healing elastomers using commercial tire-grade polybutadiene rubber (BR) and butyl rubber (IIR). The elastomeric chains were directly grafted with optimized dosages of maleic anhydride followed by reactive mixing with ring opening amine-based adducts (e.g., 3-Amino-1, 2, 4-triazole) to create acid/amide-based supramolecular cooperative hydrogen bonds between elastomer chains, without any adverse effect on the intrinsic properties of the elastomers. Thus, modified elastomers in gum state were found to be have supramolecular cross-linking, that is, without applying any conventional vulcanizing agents. The tensile strength and tensile modulus of Modified BR, that is, BR-g-MAH (Tz) were enhanced by ~3.5% and ~7.5% respectively compared to commercial BR due to incorporation of hydrogen bonding network. The modified elastomers were also found to be thermo-responsive in which micro-cracks were healed in presence of thermal stimuli. Such healing could have been observed due to presence of reversible hydrogen-bonding based dissociation and association phenomenon. The thermo-reversible supramolecular hydrogen bonding was observed in 1H NMR spectroscopy as well. Furthermore, such modified BR, when utilized in different pneumatic tire formulations, significantly improvement in dynamic property was observed as compared to tire formulation made using commercial grade BR. The modified elastomer showed potential to replace the commercial-grade elastomers for various conventional elastomers applications especially in tire sidewalls, tire tread etc. Additionally, such modified BR may improve tire life cycle, and thereby, reduces tire-waste generation. It may also find applications in non-tire sectors like conveyer belts, sealing joints, impact protection etc.

Extraction and Characterization of Pharmaceutical Grade Microcrystalline Cellulose From Bambara Nut (Voandzeia Subterranean (L) Thousars) Husk

Microcrystalline cellulose is a vital ingredient in the food, pharmaceutical, and cosmetics industries. In this study, Bambara nutshell microcrystalline cellulose (BNS-MCC) was prepared by acid hydrolysis modification of Bambara nutshell alpha-cellulose pulp. The sample was subjected to sodium hydroxide pulping (2.0% and 17.5% NaOH respectively) and a multistage pulping treatment using 3.5% nitric acid. The analysis results showed that the pulping method was effective for substantial removal of lignin with a 14.416% yield of alpha-cellulose pulp. The organoleptic and physicochemical properties of BNS-MCC were examined. The prepared BNS-MCC powder was examined using a Scanning Electron Microscope (SEM), Fourier Transform Infrared spectroscopy (FTIR), and X-ray Diffractometer (XRD). The sample’s powder flow properties (true density, Hausner index, Carr’s index, angle of repose,powder porosity, loss on drying, and moisture sorption capacity) were (1.216g/mL, 1.34, 25.75%, 39.80o, 64.7%, and 46.81%). The results of the analysis of the BNS-MCC compared well with commercial grades and conformed to US Pharmacopeia (USP) and British Pharmacopeia specifications. This result shows that Bambara nutshells have potential application for pharmaceutical grade cellulose production used in direct compression tableting.

The roles of polymer relaxation phenomena, aqueous dye solubility and the physical properties of water in the mechanism of adsorption of a disperse dye on poly(ethylene terephthalate) fibres: Part 3 physical properties of water and water‐derived fibre properties

AbstractIn the absence of published information regarding the temperature dependency of water‐derived poly(ethylene terephthalate) fibre properties, the findings reported for the thermally regulated interactions between water and 100% amorphous poly(ethylene terephthalate) materials were interpreted from the perspective of the amorphous domains that reside within semi‐crystalline polyester textile fibres. This analysis suggests that the pronounced temperature dependent uptake of a commercial grade disperse dye on poly(ethylene terephthalate) fabric achieved during an aqueous dyeing process at temperatures between 30 and 130°C is the likely result of the combination of three separate, but inherently inter‐related, thermally activated phenomena, namely, polymer structural relaxation, in which polymer glass transition assumes a dominant role, dissolution of disperse dye in the aqueous dyebath, as well as various water–fibre interactions, in the guise of water sorption, water molecule diffusivity, water‐induced swelling and water‐induced plasticisation. Although thermally regulated macromolecular relaxation processes adopt the principal role in dye uptake, temperature dependent dye solubility and water‐derived fibre properties nevertheless likely provide crucially important supportive roles.

Ultrasonic evaluation of aging kinetics in amorphous polymer

The physical aging of amorphous polymers induces changes in material properties, which are challenging to detect in situ in industrial settings. Here, we present a nondestructive nonlinear ultrasonic evaluation technique that enables localized measurements of the combined effects of temperature and time in amorphous polymers, without needing to remove materials. The proposed technique is demonstrated using commercial grade poly(vinyl chloride) samples and is supported by analysis of wave–material interactions. The results show that the physical aging of the polymer is described by the Arrhenius equation with an effective activation energy of 103 kJ/mol over the analyzed temperature range.

Fabrication and characterization of bio-nanocomposite films using κ-Carrageenan and Kappaphycus alvarezii seaweed for multiple industrial applications

In the present study, the whole seaweed from Kappaphycus alvarezii (containing carrageenan) was used for preparation of bio-nanocomposite films by blending with metal oxide nanoparticles such as zinc oxide (ZnONPs), cupric oxide (CuONPs) and silicon dioxide (SiO2NPs) for multiple applications, and their properties were compared with standard refined κ-Carrageenan (commercial grade). Simultaneously, the antibacterial activity and biodegradation profile of the prepared bio-nanocomposite film were also studied. The incorporation of nanoparticles into the bioplastic film matrices altered the surface morphology, increased the roughness and significantly (p < 0.05) reduced the UV transmittance, water uptake ratio (WUR), moisture content and solubility in both standard carrageenan-based bio-nanocomposite films (CBF) and Kappaphycus- based bio-nanocomposite films (KBF) compared to control. The average roughness (Ra) of KBF increased compared to CBF; however, CBF showed better tensile strength compared to KBF. Both KBF and CBF loaded with nanoparticles exhibited strong antibacterial activity against Staphylococcus aureus and Escherichia coli. However, KBF performed better compared to CBF. Antimicrobial effect of nanoparticles delayed the degradation of the bio-nanocomposite films. The present study proposes that the whole seaweed (Kappaphycus alvarezii) can be used directly for multiple industrial applications.

Linear Dual-Series Mach Zehnder Modulator Employing Electrostatic Doping for Photonic Integrated Circuits

In this paper, we propose a highly linear electrostatic doping (ED) assisted dual series Mach-Zehnder modulator (MZM) suitable for photonic integrated circuits (PICs). A complete simulation study on the performance of the proposed dual series MZM is incorporated in this paper. We have analytically formulated the steady-state and the nonlinear performance of the proposed modulator and the simulation results using commercial grade photonic circuit simulator are also incorporated in support of the analytical study. Simulation results show that the proposed modulator can offer <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim\!\!16$</tex-math></inline-formula> dB of static extinction ratio (ER) with 3.2 dB of insertion loss (IL). The modulator offers approximately 10.2 dB of dynamic ER at 10 Gb/s data rate. The effect on the transfer function of the dual-series MZM due to the imbalance in the driving RF signals is also discussed supported with simulation results. The nonlinear performance of the proposed modulator is also estimated using analytical method and dual-tone test method. Results indicate that the spurious free dynamic range (SFDR) of the proposed dual series MZM for second and third order intermodulation distortions (IMD2 and IMD3) are 96.11 dB.Hz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{1/2}$</tex-math></inline-formula> , and 132.4 dB.Hz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2/3}$</tex-math></inline-formula> , respectively. Study of the transient performance also reveals that the 3-dB electro-optic bandwidths are 11.39 GHz and 8.32 GHz for single and dual-series ED-assisted MZM, respectively.

Effect of stretch limit change on hyperelastic dielectric actuation of styrene–ethylene/butylene–styrene (SEBS) copolymer organogels

Harder dielectric elastomers are structurally stronger than soft ones but hardly actuate under electrostatic pressure. It remains unclear which property limits harder dielectric elastomers from producing as large actuation as soft ones. This study shows that the change in stretch limit rather than modulus bounds the ultimate dielectric actuation. A larger ultimate stretch warrants a pre-stretched membrane to further thin down and expand biaxially relative to the pre-stretch state. Theory and experiments showed that pre-stretch alters the maximum stretchability and ultimate dielectric actuation. An optimal pre-stretch helps maximize the ultimate actuation close to times radially so long as the corresponding total stretch did not exceed the elastomer’s fracture limit. Hence, a stretchy harder dielectric elastomer stands a chance of producing as large ultimate actuation as soft ones do. To validate the theory, we tested three commercial grades of styrene–ethylene/butylene–styrene copolymers (SEBS) organogels with different oil content and shore hardness. The tests showed that a 20 A-hardness organogel of low toughness actuated less ultimately, but a 10 A-hardness organogel of greater toughness actuated as much as an 8 A-hardness organogel does. This 10 A-hardness SEBS organogel showed an ultimate elongation of 1192%, and 3.1 times the shear modulus and seven times the tensile strength of 3 M VHB 4910. When being optimally pre-stretched for 3.5 times radially, it produced a substantial hyperelastic dielectric actuation up to 104% active areal strain at 277 MV m−1, comparable to the actuation generated by the over-stiffened VHB DEAs. Unlike VHB DEAs, these harder SEBS DEAs generated hyperelastic actuation free from severe viscoelastic drift. The high performance of SEBS organogels can potentially meet the need for forceful artificial muscles to drive bio-inspired robots.

Disinfection and Biocompatibility of Titanium Surfaces Treated with Glycine Powder Airflow and Triple Antibiotic Mixture: An In Vitro Study.

The aim of this in vitro study was to compare three disinfection protocols of biofilm-coated machined (MAC) and acid etched (SLA) commercial pure Grade 4 Titanium disks. Samples were infected with a vial of polymicrobial biofilm to simulate peri-implantitis in vitro. Seventeen MAC and twenty SLA titanium disks were randomly assigned to: (1) glycine powder air-flow (GYPAP) for 1 min; (2) a local delivered triple paste antibiotic composed by a gel mixture with ciprofloxacin, metronidazole, and clarithromycin (3MIX) for 1 h; and (3) a combination of both (GYPAP + 3MIX). Biocompatibility of the titanium disks after each treatment protocol was assessed by measurement of adhesion and growth of adipose-derived mesenchymal stem cells (ASCs) after 24 and 72 h. A confocal laser scanning microscope (CLSM) assessed the antibacterial effect of each treatment. Data of the antibacterial efficacy and cell viability were presented as mean with standard deviation and calculated by one-way ANOVA with multiple comparisons via Bonferroni tests. Results were considered significant with p < 0.05. The higher cell viability was achieved by the 3MIX and GYPAP combination on the SLA surfaces after 72 h. CLSM analysis showed a mean ratio of dead bacteria statistically higher in the 3MIX + GYPAP group compared with the GYPAP and 3MIX subgroups (p < 0.05). In conclusion, data showed that the combination of GYPAP and 3MIX could be preferred to the other protocols, especially in presence of SLA titanium surface.

A Novel Cell Delivery System Exploiting Synergy between Fresh Titanium and Fibronectin.

Delivering and retaining cells in areas of interest is an ongoing challenge in tissue engineering. Here we introduce a novel approach to fabricate osteoblast-loaded titanium suitable for cell delivery for bone integration, regeneration, and engineering. We hypothesized that titanium age influences the efficiency of protein adsorption and cell loading onto titanium surfaces. Fresh (newly machined) and 1-month-old (aged) commercial grade 4 titanium disks were prepared. Fresh titanium surfaces were hydrophilic, whereas aged surfaces were hydrophobic. Twice the amount of type 1 collagen and fibronectin adsorbed to fresh titanium surfaces than aged titanium surfaces after a short incubation period of three hours, and 2.5-times more fibronectin than collagen adsorbed regardless of titanium age. Rat bone marrow-derived osteoblasts were incubated on protein-adsorbed titanium surfaces for three hours, and osteoblast loading was most efficient on fresh titanium adsorbed with fibronectin. The number of osteoblasts loaded using this synergy between fresh titanium and fibronectin was nine times greater than that on aged titanium with no protein adsorption. The loaded cells were confirmed to be firmly attached and functional. The number of loaded cells was strongly correlated with the amount of protein adsorbed regardless of the protein type, with fibronectin simply more efficiently adsorbed on titanium surfaces than collagen. The role of surface hydrophilicity of fresh titanium surfaces in increasing protein adsorption or cell loading was unclear. The hydrophilicity of protein-adsorbed titanium increased with the amount of protein but was not the primary determinant of cell loading. In conclusion, the osteoblast loading efficiency was dependent on the age of the titanium and the amount of protein adsorption. In addition, the efficiency of protein adsorption was specific to the protein, with fibronectin being much more efficient than collagen. This is a novel strategy to effectively deliver osteoblasts ex vivo and in vivo using titanium as a vehicle.

Proximate Analysis and Production of Bio-ethanol from Sweet Potato (Ipomoea batatas) White Cultivars obtained from Samaru Zaria

This study entails the production of bioethanol from the peels of sweet potato of white cultivar variety obtained in Zaria, Kaduna State Nigeria. Fresh cultivar with the proximate composition of 72% moisture content, 9.71% ash content, 24.52% crude fiber, 78.74% total carbohydrate and crude protein of 6.42% were hydrolyzed with 3% sulphuric acid solution at 130oC and 60 minutes in an improvised reactor to generate 54.5ml of hydrolyzate after steam pretreatment step. The fermentable reducing sugar of 10.68% was achieved through glucose standardization with UV-spectrophotometer at 540nm wavelength. The fermentation of the hydrolyzate –yeast/media mixture (155ml) at 30oC for 72hours was achieved by commercial grade saccharomyces cerevisiae to yield 20.5g/54.5ml, which corresponds to 0.8198g/ml specific gravity and 93.6% ethanol concentration. The molecular sieve was eventually adopted in dehydrating the bioethanol to 99.9% (0.8072g/ml) concentration and the final yield of 1.61% per 50g of w. cultivar. FTIR spectrum that declares the ethanolic identity with the stretching vibrations of O-H, C-O and C-H at 3391, 1055 and 2981cm-1 respectively with the symmetric stretching vibration of the methyl groups at 2930cm-1.

Determination of Impurities in Graphite Using Proton Induced Gamma Ray Emission, Total Reflection X-ray Fluorescence and Instrumental Neutron Activation Analysis

Determination of impurities in graphite is very important for its quality control, as their presence even at trace level can affect the performance of graphite in various applications. Graphite with equivalent boron content (EBC) less than 5 mg kg-1 is considered as nuclear grade. Elements with high neutron absorption cross section (boron and rare earths) contribute significantly to EBC. Non-destructive method is preferred as there is no sample processing and probability of loss of volatile elements while digestion. Proton Induced Gamma Ray Emission (PIGE), Instrumental Neutron Activation Analysis (INAA) were utilized for the non- destructive determination of impurities in both nuclear and commercial grade graphite. Low Z elements like Li, B, F, Na, Al and Si were detected in graphite by PIGE whereas Na, K, Sc, Cr, Mn, Fe, Co, Zn, Rb, Zr, Sb, Cs, La, Ce, Nd, Sm, Eu, Tb, Yb, Hf, Ta, Th were determined using INAA. Few elements like Ca, Ti, V, Ni, Sr and Pb remained undetected by both the non-destructive techniques. These elements were determined by Total Reflection X-ray Fluorescence (TXRF) after digestion of the graphite samples by dry ashing. Combinations of these techniques were utilized to get maximum information regarding the impurities present in graphite.

Influence of cutting through the middle vein of tobacco leaves on the technological properties of raw materials of the Virginia 202 variety of various drying methods

The Virginia 202 tobacco variety, selected by FSBSI ARSRITMTP for the production of smoking tobacco, is in high demand. Intensification of post-harvest processing of large leaves of a variety with a massive middle vein is proposed to be carried out by cutting through the middle vein, which will reduce the drying time and energy costs. Studies have been conducted on the use of this method and the quality indicators of tobacco raw materials of natural and combined drying methods has been assessed. It has been found that the cutting technique shortens the drying time with the combined method by 2.8 times, with the natural method by 2.3 times, while the commercial quality improves when drying by the combined method, the yield of 1 commercial grade makes 86.5%, the taste qualities of raw materials improve, due to an increase in the ratio of carbohydrate-protein balance to 1.08–1.5; the strength is preserved, due to less nicotine consumption during a shorter drying period; fiber yield increases by 3–5%. The volume-elastic properties of the fiber affect the consumption of raw materials in the smoking product. The fiber of natural drying of raw materials reduces its consumption for the production of smoking products, the fiber of combined drying of raw materials obtained using high temperatures of drying of the vein increases the consumption of raw materials by 18.65%. The aim of the research is to determine the elastic properties of the cut vein present in the fiber of combined drying. The vein has been flattened and its elastic properties have been determined. It has been established that the recoil value of the flattened uncut vein is 6.0% greater, the undisturbed structure of the middle vein has a greater degree of volume recovery and better elastic properties. An increase in the elastic properties of the raw materials of combined drying can be carried out due to its preparation in a differentiated way, with the allocation of the middle vein, the method of striping and, separately, the preparation of the vein and the leaf plate. When preparing, moistening and flattening the cut vein, which has a better moisture-absorbing ability and a lower destructive load when it is flattened by 2.2 times, it is possible to reduce energy consumption for these technological processes.

Influence of Processing Technology on Creep Damage of Ultrafine-Grained Titanium

This work deals with the influence of the processing technology of ultrafine-grained titanium by the application of severe plastic deformation (SPD) on its degradation processes in creep at elevated temperatures. Commercial grade titanium heats with different content of carbon were processed by multi-stage rolling. Creep tests under constant tensile stress were performed in a protective atmosphere of argon at a temperature of 673 K with application of different stress levels. The microstructure of the fractures creep specimens were analysed by metallographic and fractographic analyses using scanning and transmission electron microscopy (SEM, TEM). Under the same creep loading conditions the heat with higher content of carbon exhibited better creep resistance due to stronger effect of precipitation hardening by titanium carbides.