Journal articles: 'E. H. Purdy Manufacturing Co' – Grafiati (2024)

Abstract:

This research aims to characterize and examine the microstructure and mechanical properties of the newly developed M789 steel, applied in additive manufacturing. The data presented herein will bring about a broader understanding of the processing–microstructure–property–performance relationships in this material based on its chemical composition and heat treatment. Samples were printed using the laser powder bed fusion (LPBF) process and then the solution was annealed at 1000 °C for 1 h, followed by aging at 500 °C for soaking times of 3, 6 and 9 h. The AM components showed a relative density of 99.1%, which arose from processing with the following parameters: laser power of 200 W, laser speed of 340 mm/s, and hatch distance of 120 µm. Optical and electron microscopy observations revealed microstructural defects, typical for LPBF processes, like voids appearing between the melted pools of different sizes with round or creviced geometries, nonmelted powder particle formation inside such cavities, and small spherical porosity that was preferentially located between the molten pools. In addition, in heat-treated conditions, AM maraging steel has combined oxide inclusions of Ti and Al (TiO2:Al2O3) that reside along the grain boundaries and secondary porosities; these may act as preferential zones for crack initiation and may increase the brittleness of the AM steel under aged conditions. Consequently, the elongation of the AM alloy was low (<3%) for both annealed and aged solution conditions. The tensile strength of AM M789 increased from 968 MPa (solution annealed) to 1500–1600 MPa after the aging process due to precipitation within the intermetallic η-phase. A tensile strength and yield point of 1607 ± 26 and 1617 ± 45 MPa were obtained, respectively, after a full heat treatment at 500 °C/6 h. The results show that 3 h aging of solution annealed AM M789 steel achieves satisfactory material properties in industrial practice. Extending the aging time of printed parts to 6 h yields slightly improved properties but may not be worth the effort, while long-term aging (9 h) was shown to even reduce quality.

Abstract:

AbstrakMetoda pemaduan mekanik adalah reaksi padatan dari beberapa logam dengan memanfaatkan proses deformasi untuk membentuk suatu paduan. Pada penelitian ini dibuat paduan Co-Cr-Mo dengan proses wet milling dengan variasi waktu milling selama 3, 5, 10, 20, dan 30 jam. Proses wet milling sangat efektif untuk mencegah terjadinya oksidasi dan juga memicu pembentukan paduan Co-Cr-Mo dengan baik. Hasil XRD menunjukkan bahwa telah terjadi pertumbuhan fasa γ pada durasi milling 3, 5, 10, 20, dan 30 jam, berturut-turut sebesar 42,80 %; 67,61 %; 82,94 %, 84,63 % dan 88,92 %. Ukuran kristalit fasa γ sebesar 25,9 nm; 12,5 nm; 5,1 nm dan 4,9 nm seiring dengan meningkatnya waktu milling. Disimpulkan bahwa telah berhasil dilakukan pembuatan paduan nanokristalin Co-Cr-Mo dengan metode pemaduan mekanik lebih dari 85 % dengan waktu milling minimum selama 30 jam. Kata kunci : Co-Cr-Mo, pemaduan mekanik, nano-kristalin AbstractSynthesis of Co-Cr-Mo nano-crystalline by mechanical alloying has been carried out. Mechanical alloying is a solid state reaction of some metals by utilizing the deformation process to form an alloy. In this research, parameter milling time used for making Co-Cr-Mo alloy by wet milling process is 3, 5, 10, 20 and 30 h. Wet milling process is very effective to prevent oxidation and triggers the formation of fine Co-Cr-Mo alloys. Results of XRD pattern refinement shows that Co-Cr-Mo alloys was growth by percentage approximately around 42.80%, 67.61%, 82.94%, 84.63% and 88.92% for milling time 3, 5, 10, 20, and 30 h, respectively. Otherwise, crystalline size measurement after milling time 5, 10, 20, and 30 h obtained around 25.9 nm, 12.5 nm, 5.1 nm and 4.9 nm, respectively. This research concluded that the optimum milling time could obtained synthesizes nano-crystalline of Co-Cr-Mo alloy more than 85% is 30 h. Keywords: Co-Cr-Mo alloy, mechanical alloying, nano-crystalline

Abstract:

The simultaneous production of microbial polymers levan and poly[3-hydroxybutyrate] (PHB), a type of polyhydroxyalkanoates, was investigated in this work. The study involved the fermentation of sucrose and molasses by H. smyrnensis AAD6T (BAE2 strain) to produce PHB (intracellular) and levan (extracellular). Both polymers were isolated and characterized by FTIR. Levan was also characterized by thin-layer chromatography (TLC) and viscosimetric analysis. The amount of biomass was 25 g until the end of fermentation. The PHB rate was 0.015 g in both media and the average PHB productivity was 6.0 x 10-4 g PHB/g biomass. The highest rate of levan was 9 g/L in the range of 72–80 h, in the molasses-based medium. The FTIR spectra showed specific signals for each of the polymers, such as the peak at 1700 for the carbonyl group of esters for the PHB and signals at 900 and 800, which are typical signals for levan fructose rings. Furthermore, acid hydrolysis of levan revealed that it was formed only by fructose, as confirmed by TLC With this study, H. smyrnensis AAD6T BAE2 co-produced PHB and levan using a low-cost carbon source, showing great potential in reducing biopolymer manufacturing costs.

Abstract:

Ross Macdonald is the CEO and Managing Director of Cynata Therapeutics Limited (Australia). He has over 30 years of experience and a track record of success in pharmaceuticals and biotechnology businesses. His career history includes positions as Vice President of Business Development for Sinclair Pharmaceuticals Ltd (now Sinclair IS Pharma), a UK-based specialty pharmaceuticals company, and Vice President of Corporate Development for Stiefel Laboratories, Inc., then the largest independent dermatology company in the world and acquired by GlaxoSmithKline in 2009 for £2.25 billion. He has also served as the CEO of Living Cell Technologies Ltd, Vice President of Business Development of Connetics Corporation and Vice President of Research and Development of F H Faulding & Co Ltd.

Abstract:

Silicon-based power device performances are largely affected by metal contamination occurring during device manufacturing. Among the usual gettering techniques, recent developments were done on high dose helium implantation. Even though the gettering efficiency of this technique has been demonstrated in device application, the required doses are still extremely high for an industrial application. Recently, it has been shown that the use of H/He co-implantation limits the total requested doses [1]. In this paper, co-implantation of H/He, which has been already used to reduce the dose in the smart-cut® process is explored. The goal of this work is to decrease efficiently the implanted dose maintaining an efficient metallic gettering without degrading the Si surface. The impact of H implantation on He implantation induced defects is carefully studied. The TEM observations have evidenced that hydrogen addition drastically modified the defect band structure and promotes the cavity growth.. Additionally, we demonstrate that an efficient gettering can be obtained.

Abstract:

Orange rust of sugarcane caused by Puccinia kuehnii was detected in Florida in 2007 (1). It was hypothesized that the pathogen originated from Africa because brown rust of sugarcane (synonym common rust) was introduced to the Western Hemisphere from Africa (3). Requests for rust-infected sugarcane samples were made to several western and central African countries to investigate if orange rust of sugarcane was present but as yet undetected. Orange rust had not previously been reported from western or central Africa. At Zuénoula, Ivory Coast in July 2009, symptoms of sugarcane rust were observed on cvs. SP 71-6180 and Co 997 and appeared distinct to those of brown rust of sugarcane. A year later (May 2010), rust-infected specimens of SP 71-6180 and Co 997 from the same location and also from Borotou in Ivory Coast were sent to the USDA-ARS Systematic Mycology and Microbiology Laboratory in Beltsville, MD for identification. Also in May 2010, sugarcane rust was observed at Mbandjock and Nkoteng in Cameroon on cvs. D 88172, FR 87482, and RB 72-454 and on breeding clones RCmr 08/319 and RCmr 08/1121. All specimens had orange uredinial lesions that ranged from 0.6 to 6.5 mm × 200 to 300 μm and were ellipsoidal to elongate. Urediniospores were consistent with P. kuehnii E.J. Butler observed on specimens from Florida (1). DNA isolated from all samples was successfully amplified with P. kuehnii specific primers targeting ITS1 of rDNA (2). The nuclear large subunit region of rDNA of the rust specimens from Ivory Coast (BPI 881015–881017, GenBank Accession No. HQ666888) and Cameroon (BPI 881010–881014, GenBank Accession Nos. HQ666889–HQ666891) were sequenced. DNA sequences for all were identical to sequences of P. kuehnii and distinct from known sequences of P. melanocephala available in GenBank. To our knowledge, this is the first confirmed report of orange rust of sugarcane in western and central Africa. There is evidence that brown rust of sugarcane was introduced to the Western Hemisphere from this region of Africa (3) making it also the likely source of introduction of orange rust. Further experimentation is required to confirm this hypothesis. References: (1) J. C. Comstock et al. Plant Dis. 92:175, 2008. (2) N. C. Glynn et al. Plant Pathol. 59:703. 2010. (3) H. L. Purdy et al. Plant Dis. 69:689, 1985.

Abstract:

The monitoring of environmental contamination is an important issue to protect human health and the atmospheric environment. In this study, the optical imaging of mesh structures not coated and coated with platinum was performed to analyze the optical characteristics of the lattices. A nickel monolith catalyst was manufactured via additive manufacturing and coated with platinum, and it was presented to characterize the catalyst properties. The analysis focused on the process of coating using hydrazine bath as a reducing agent. The results showed an increase in the thickness of the coating with baths with durations of 1.5 h, 2.0 h and 2.5 h. The coating thickness was strongly dependent on time duration. The SEM images and EDX were used to confirm the process of coating and analyze the presence of platinum on the catalyst. Coating layers were very thin, and others were not hom*ogeneous over the surface. When the catalyst was exposed to platinum for 2.5 h, the catalyst showed an efficiency of 0.06% for NOx, 0.10%, for CO and 0.09% for HC reduction.

Abstract:

Numerical investigation was carried out to study the heat transfer performance for a high-speed rotating cylindrical surface subjected to single row array round jets impingement, under a very small gap spacing. Various parameters that affect heat transfer, such as the fluid density, flow velocity and Nusselt number distributions of the radius clearance were studied based on varied nozzle to target surface spacing H and mass flow rate. It has been found that the fluid density was a dominant factor and the velocity was the secondary factor for the gas jet heat transfer performances. The overall heat transfer was improved with a reduction in the number of nozzles, for given inlet mass flow rate boundary conditions. The decrease of H/di (di, nozzle diameter) may have positive or negative effects on the heat transfer performance from the impingement surface. Reducing the radius gap H, for a certainty, increases the average density of the fluid in the clearance, which is desirable in applications that enhance heat transfer performance. But when the radius gap (H) is small enough, increasing di may have a negative impact on heat transfer.

Abstract:

The recycling of critical metals like cobalt and nickel from spent lithium-ion batteries (LIBs) is of immense importance in sustainable manufacturing. This work aims to purify Co(II) and Ni(II) present in acidic and ammonia solutions using ion exchange. AG-1-X8 resin modified with thiocyanate anions (R₄N⁺SCN⁻ resin) was used to separate a small amount of Co(II) from HCl and H₂SO₄ solutions containing Ni(II) and Si(IV) at pH 3, and the effect of factors such as pulp density, shaking time, and Ni(II) concentration on the adsorption of Co(II) was investigated. The difference in the adsorption behaviour of metal ions onto the R₄N⁺SCN⁻ resin from HCl and H₂SO₄ solutions was insignificant. Increasing the Ni(II) concentration in the feed negatively affected the loading efficiency of Co(II). The complete elution of the metals from the loaded resin was attained with a 5% NH₃ solution. Purolite C100 resin was selected for the purification of Co(II) from a 10% (v/v) NH₃ solution containing a small amount of Ni(II), and the best conditions for the complete adsorption of both Co(II) and Ni(II) were determined. Selective elution of Ni(II) over Co(II) from the loaded resin was achieved by dilute H₂SO₄ solution. The purity of Co(II) in the solution after elution with 2.0 mol/L H₂SO₄ from the Ni(II) free resin was higher than 99.99%. Ion exchange was effective for purifying a weak acidic or ammonia solution in which there is a significant difference in the Co(II) and Ni(II) concentrations.

Abstract:

Celem badań była ocena przeżywalności wybranych szczepów bakterii Lactobacillus wyizolowanych z sera oscypkowego i korycińskiego w warunkach in vitro modelu przewodu pokarmowego w zależności od zastosowanych dodatków żywnościowych. Zakres prac obejmował ocenę przeżywalności bakterii po 2 i 5 h inkubacji w modelowym układzie symulującym pasaż żołądkowo-jelitowy w zależności od zastosowanego dodatku ochronnego: mleka UHT (o zawartości tłuszczu 3,2 %), śmietanki (o zawartości tłuszczu 36 %), a także 10-procentowych roztworów inuliny i oligofruktozy. Wykazano, że badane szczepy były op*rne na sok żołądkowy o pH = 2,5, natomiast model soku żołądkowego o pH = 2 powodował zmniejszenie żywotności bakterii średnio o ok. 5 rzędów logarytmicznych po 2 h inkubacji. Mleko UHT wykazało nieznaczne działanie ochronne na przeżywalność komórek bakterii, porównywalne do inuliny i oligofruktozy w środowisku obniżonego pH, przy zastosowanej metodzie badawczej. Istotny efekt ochronny na przeżywalność komórek bakterii badanych szczepów stwierdzono natomiast w przypadku zastosowania śmietanki, co najprawdopodobniej ma związek z większą zawartością tłuszczu w porównaniu z jego zawartością w mleku. Badane szczepy, Lb. plantarum (Kor1 oraz Os1) wyizolowane z żywności, charakteryzowały się podobnymi właściwościami jak szczep referencyjny Lb. plantarum 299v, co świadczyć może o potencjalnych właściwościach probiotycznych w tym zakresie. Przeprowadzone badania wskazują na zasadność dalszych badań potwierdzających probiotyczne właściwości i potencjalne zastosowanie jako probiotyków bakterii wyizolowanych z żywności fermentowanej.

Abstract:

Abstract Due to their small size, low-power demands, and customizability, low-cost sensors can be deployed in collections that are spatially distributed in the environment, known as sensor networks. The literature contains examples of such networks in the ambient environment; this article describes the development and deployment of a 40-node multi-hazard network, constructed with low-cost sensors for particulate matter (SHARP GP2Y1010AU0F), carbon monoxide (Alphasense CO-B4), oxidizing gases (Alphasense OX-B421), and noise (developed in-house) in a heavy-vehicle manufacturing facility. Network nodes communicated wirelessly with a central database in order to record hazard measurements at 5-min intervals. Here, we report on the temporal and spatial measurements from the network, precision of network measurements, and accuracy of network measurements with respect to field reference instruments through 8 months of continuous deployment. During typical production periods, 1-h mean hazard levels ± standard deviation across all monitors for particulate matter (PM), carbon monoxide (CO), oxidizing gases (OX), and noise were 0.62 ± 0.2 mg m−3, 7 ± 2 ppm, 155 ± 58 ppb, and 82 ± 1 dBA, respectively. We observed clear diurnal and weekly temporal patterns for all hazards and daily, hazard-specific spatial patterns attributable to general manufacturing processes in the facility. Processes associated with the highest hazard levels were machining and welding (PM and noise), staging (CO), and manual and robotic welding (OX). Network sensors exhibited varying degrees of precision with 95% of measurements among three collocated nodes within 0.21 mg m−3 for PM, 0.4 ppm for CO, 9 ppb for OX, and 1 dBA for noise of each other. The median percent bias with reference to direct-reading instruments was 27%, 11%, 45%, and 1%, for PM, CO, OX, and noise, respectively. This study demonstrates the successful long-term deployment of a multi-hazard sensor network in an industrial manufacturing setting and illustrates the high temporal and spatial resolution of hazard data that sensor and monitor networks are capable of. We show that network-derived hazard measurements offer rich datasets to comprehensively assess occupational hazards. Our network sets the stage for the characterization of occupational exposures on the individual level with wireless sensor networks.

Abstract:

Currently, most of household goods are made from polymer or plastic. The polymer manufacturing industry has been relying on fossil fuel-based raw materials which is non-biodegradable. Plastics derived from these non-biodegradable sources will be difficult to degrade in nature, which in turn will pollute the environment and harm the ecosystem. One way to reduce the ecosystem damages caused by plastic made from petroleum-based plastic is to use biodegradable materials as plastic industry raw materials, such as Polyhydroxyalkanoates (PHA). Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) or PHBV is an example of PHA that can be produced by several types of microorganisms, such as marine archaea Haloferax mediterranei. This objective of this study is to determine the productivity of marine archaea cultures H. mediterranei to produce PHBV with yeast extract as main nutrient sources. H. mediterranei will produce PHBV at extreme conditions with excess carbon and limited nutrients. Experiments and analysis were conducted in triplicate and batch operating systems. During the fermentation process, Optical Density, glucose levels, phosphorus levels, pH, and Dry Cell Weight (DCW) were observed. The final product then analysed using GC-MS to determine the PHBV content and 3HB (3-hydroxybutyrate) and 3HV (3-hydroxyvalerate) fraction composition in the PHBV. The results show that the maximum specific growth rate and doubling time (Td) of the H. mediterranei were 0.1258 hours-1 and 5.51 hours. H. mediterranei biomass were increasing until it reached stationary phase at 95 hours. The results show PHBV content, dry biomass and yield PHA to substrate were 2.62 g/L, 29.1% and 0.27 g/g.

Abstract:

Enterococcus faecium 7C5 produces a bacteriocin active against Listeria monocytogenes and Listeria innocua. In co-cultures of the strain 7C5 with a thermophilic starter, which was composed of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, the acidifying activity of the latter was not affected. In contrast, the rate of bacteriocin production was lower when compared with the pure culture of strain 7C5. In co-cultures of L. innocua CNRZ LIN 11 with the thermophilic starter or with strain 7C5, a bacteriostatic effect on Listeria growth was observed. In the co-culture of L. innocua with both strain 7C5 and the thermophilic starter, a complete listerial inhibition occurred. The combined inhibitory effect of the pH decrease and bacteriocin production, which were shown to be synergistic, was demonstrated both at 37°C and under temperature conditions reproducing the first 24 h of a soft-cheese technology. This data substantially supported the potential of using bacteriocin-producing strains as a culture adjunct to inhibit Listeria during cheese manufacturing.

Abstract:

Rechargeable lithium–oxygen (Li-O2) batteries represent state-of-the-art electrochemical energy storage devices that provide high energy densities. However, their commercialization is challenging owing to their low charging/discharging efficiencies, short battery lives, high overpotentials, and high cathode manufacturing costs. In this study, we prepared a metal-free, N,P co-doped, porous activated carbon (N,P-PAC) electrode via KOH activation and P doping for application as a Li-O2 battery cathode. When used in a rechargeable Li-O2 battery, the N,P-PAC cathode showed a high specific discharge capacity (3724 mA h g−1 at 100 mA g−1), an excellent cycling stability (25 cycles with a limit capacity of 1000 mA h g−1), and a low charge/discharge voltage gap (1.22 V at 1000 mA h g−1). The N,P-PAC electrode showed a low overpotential (EOER-ORR) of 1.54 V. The excellent electrochemical performance of the N,P-PAC electrode can mainly be attributed to its large active area and oxygen-containing functional groups generated via KOH activation and P-doping processes. Therefore, the N,P-PAC prepared in this study was found to be a promising eco-friendly and sustainable metal-free cathode material for Li-O2 batteries.

Abstract:

Solid particle emissions from burning wood in three internal combustion biomass cooking stoves commonly used in southern Chile were compared. Each stove was used to show differences in sealing systems, combustion chamber shape, and heating surfaces in order to optimize biomass combustion and the energy produced at a low manufacturing cost. The influence of cooking stove design along with particle and gas emissions that resulted from the biomass combustion within the cooking stove was investigated in this study. Levels of diverse atmospheric contaminants, such as particulate matter, emission factor, NOx, CO2, and CO, and the temperature of the flue gases were determined with the Ch-28 method and UNE-EN 12815. The average emission of particulate matter was significantly reduced by modifying the geometry of the combustion chamber and heating surface of each stove, resulting in 5 g/h particle emissions in conventional equipment and 2 g/h in the improved equipment. In relation to gas emissions, there was a 25% maximum decrease in NOx gases and 35% in CO after modifying the heating surface of each stove. This background supports the evidence of technological improvement with high environmental impact and low economic cost for local manufacturers.

Abstract:

In many countries, most of household goods are made from polymer or plastic. The polymer manufacturing industry has been relying on fossil fuel-based raw materials which are non-biodegradable. Plastics derived from these non-biodegradable sources will be difficult to degrade in nature, which in turn will pollute the environment and harm the ecosystem. One way to reduce the ecosystem damages caused by petroleum-based plastic is by using biodegradable materials for plastic industry, such as Polyhydroxyalkanoates (PHA). Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) or PHBV is an example of PHA that can be produced by several types of microorganism, one of them is marine archaea Haloferax mediterranei. The objective of this study is to determine the productivity of marine archaea H. mediterranei cultures to produce PHBV with yeast extract as main nutrient sources. Experiments and analysis were conducted in triplicate and batch operating system. During the fermentation process, optical density, glucose levels, phosphorus levels, pH, and dry cell weight (DCW) were observed. The final product was then analysed using GC-MS to determine 3HB (3-hydroxybutyrate) and 3HV (3-hydroxyvalerate) fraction composition in the PHBV. The results showed that the maximum specific growth rate (m) and doubling time (Td) of the H. mediterranei were 0.1258 hours-1 and 5.51 hours, respectively. H. mediterranei biomass increased until it reached stationary phase after 95 hours incubation. The PHBV content, dry biomass and yield of PHBV to substrate were 2.62 g/L, 29.1% and 0.27 g/g, respectively.

Abstract:

In the Lithuanian metal working plants galvanotechnical slime is formed during the manufacturing process. It consists of Fe, Ca, Mg and combinations of microelements Cr, Mn, Co, Ni, Cu, Zn, Cd, Pb such as hydroxide, sulphide etc. To prevent contamination of the environment by metal combinations contained in the galvanotechnical slime it has to be utilized for ceramic products during the manufacturing process. In Lithuania the galvanotechnical slime is utilized for ceramzite produced in the Palemonas factory. The aim of this work is to find out whether the microelements contained in galvanotechnical slime are emitted from ceramzite into the environment while ceramzite is affected by water. There is hydromical clay in Lithuania. Cremate clay contains 70—95% of hydromicas, 5—30% kaolinite, and up to 5% of chlorite and traces of montmorillonite. It contains quartz, feldspars, calcite and limonite as well. Oxidical structure (%) is: SiO2 48–51, Al2O3 + TiO2 14—19, Fe2O3 5—8, CaO 7–11, MgO ∼ 3, K2O ∼ 3, Na2O ∼ 1, SO3 up to 0.4, loss by roasting 10—13. In producing ceramzite (1050—125°C) mullite, quartz, hematite, magnetite, anorthite, spinel, forsterite etc. are formed from clay components. If ceramzite contains galvanotechnical slime, the microelements along with ceramzite components compounds thermodynamically a few of Ca, Mg, Fe, Ni, Cu, Zn silicates and aluminates and Ca, Mg, Ni, Cu ferrites. The amount of microelements transferring from ceramzite into water has been defined with the atomicabsorption spectroscopy by keeping ceramzite granules in distilled water for 3,6 and 12 months. The results of the investigation demonstrate that the compounds of Cr, Ni, Cd, Pb, Mn, and Co do not transfer from ceramzite into water. The amounts of metallic compounds in the water C H 2 O are limited by the values of their solubility product L: C H 2 O = 5,62 Cmax L0,087, The amount of metallic compounds in the water C H 2 O depends on the extraction length according to the satiation curve. The results of the investigation show that ceramzite containing galvanotechnical slime is an ecologically clean heat insulating substance.

Abstract:

Purpose The purpose of this study is to verify how the carbon doping of the WC-Co cemented carbide (CC) affected their structure before their processing by hot isostatic pressing (HIP) technology. Design/methodology/approach The samples for this experiment were fabricated by selective laser melting technology (SLM) using a YAG fiber laser with a power of P = 40 W and a scanning speed of 83 mm/s. The subsequent carbon doping process was performed in a chamber furnace at 900 0 C for 1, 4 and 12 h. The HIP was performed at 1,390°C and pressures of 40 MPa, 80 MPa and 120 MPa. The changes induced in the structures were evaluated using X-ray diffraction and various microscopic methods. Findings X-ray diffraction analysis showed that the structure of the samples after SLM consisted of WC, W2C, Co4W2C and Co phases. As a result of the increase in the carbon content in the structure of the samples, the transition carbide W2C and structural phase Co4W2C decayed. Their decay was manifested by the coarsening of the minor alpha phase (WC), which occurred both during the carburizing process and during the subsequent processing using HIP. In the samples in which the structure was carburized prior to HIP, only the structural phases WC and Co were observed in most cases. Originality/value The results confirm that it is possible to increase the hom*ogeneity of the CC structure and thus its applicability in practice by additional carburization of the sample structure with subsequent processing by HIP technology.

Abstract:

Abstract Hematite (α-Fe2O3) nanoparticles (NPs) were chemically and thermodynamically more stable among iron oxide nanoparticles. Doping of Co2+ metal ion in α-Fe2O3 can modify the structural, optical and magnetic properties of NPs and also enhances the potential of the biomedical applications. In the current study, undoped and Co doped hematite nanoparticles were synthesised by co-precipitation method using Tribulus terrestris L. leaf extract as bio-reductant. The magnetic, optical and structural investigations were studied with the help of Ultraviolet-visible (UV-Vis), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy equipped with Energy Dispersive X-ray (SEM-EDX) Spectroscopy, Vibrating Sample Magnetometer (VSM) and X-ray Diffraction (XRD) Spectroscopy. XRD analysis shows that synthesized nanoparticles were in hematite phase, rhombohedral in structure. XRD spectral pattern clearly evidenced that prepared α-Fe2O3 and Co-Fe2O3 NPs were highly crystalline with no impurity peaks. Using VSM spectra, the M-H curve indicates that saturation magnetisation (Ms) value increases for Co-Fe2O3 NPs than undoped α-Fe2O3 NPs, it can be clearly seen that doping largely affects the magnetic nature of nanoparticles. In the UV-Vis spectra, absorption maxima increases and band gap value decreases for cobalt doped hematite nanoparticles indicating the substitution of Fe2+ ions by Co2+ ions in α-Fe2O3 lattice sites. Antidiabetic and antimicrobial activity of the synthesized undoped and Co doped hematite NPs were tested by alpha-amylase inhibitory and disc diffusion method. The Co-Fe2O3 NPs have greatly inhibited the digestive enzyme and microbial strains as compared to undoped α-Fe2O3 NPs.

Abstract:

Odwadnianie osmotyczne może być wykorzystywane m.in. jako technika suplementacji owoców i warzyw w wapń, co korzystnie wpływa na ich jakość i wartość odżywczą. Celem pracy było określenie wpływu wybranych parametrów procesu (temperatury, czasu i stężenia soli wapnia) na przebieg odwadniania osmotycznego mrożonych gruszek oraz poziom wapnia w odwadnianym materiale. W doświadczeniach użyto roztworów sacharozy o stężeniu 50 ºBx i temp. 20 ÷ 50 ºC, zawierających mleczan lub glukonian wapnia o stężeniu 0,014 ÷ 0,072 M. Wykazano, że mrożone gruszki łatwo poddają się odwadnianiu w testowanych warunkach. We wszystkich zastosowanych wariantach uzyskano ponad dwukrotny wzrost zawartości suchej substancji już po 1 h odwadniania. Po 2 ÷ 3 h wzrost zawartości suchej substancji był już znikomy. Nie obserwowano zależności ilości suchej substancji migrującej do owoców z syropu od temperatury procesu ani zastosowanej soli. W obecności mleczanu wapnia wahała się ona w granicach 1,01 ÷ 1,48 g s.s./g p.s.s, w obecności glukonianu wapnia – 0,92 ÷ 1,56 g s.s./g p.s.s. Średni ubytek wody po pierwszej godzinie odwadniania w temp. 20, 30, 40 i 50 ºC wyniósł w przypadku mleczanu wapnia odpowiednio: 2,43; 2,70; 2,70 i 2,84 g H2O/g p.s.s, a w przypadku glukonianu wapnia: 2,27; 2,74; 2,78 i 2,50 g H2O/g p.s.s. W tym czasie wystąpił jednocześnie największy przyrost zawartości wapnia w owocach, chociaż występował on także w dalszym etapach. Najwyższy poziom wapnia odnotowano po 5 h procesu prowadzonego w temp. 50 ºC z użyciem 0,072 M glukonianu wapnia – wyniósł on 1808 mg/kg. W analogicznych warunkach w obecności mleczanu wapnia zawartość ta wzrosła do 1720 mg/kg. Po pierwszej godzinie w przypadku obydwu soli poziom wapnia osiągnął wartość ok. 1300 mg/kg.