Preparation of nano-crystalline tungsten powders from gaseous WO2(OH)2

The industrial production of tungsten powder is carried out by the reduction of tungsten oxide powder via hydrogen. In this process, the size of the W particles is limited to particle sizes larger than 100 nm. To get below this limit, alternative processes are needed. In the current work, the possibility of preparing W powder below 100 nm via a vapour phase reduction of volatile WO2(OH)2 by hydrogen was investigated. The process consists of two stages. In the first stag,e WO2(OH)2 is formed by reacting WO3 with water vapour at temperatures of 1000–1100 °C. In the second stage, WO2(OH)2 is reduced by hydrogen at about 1000 °C to form metallic tungsten. The influence of process parameters such as furnace temperature, humidity and gas flow on the WO2(OH)2 evaporation and formation of tungsten powder was investigated. The characterization of the resulting powders was performed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). By optimization of the reaction conditions, powder with a metallic tungsten content of about 70 at% besides tungsten oxides was produced with metal particle sizes down to 5 nm. Further optimization should lead to a high tungsten content and a high product yield. Due to the small particle size, applications in catalysis might be possible, although an industrial realization of the process seems unrealistic at moment.

Sintesis dan Karakterisasi Selulosa Asetat dari A-Selulosa Fiber Cake Kelapa Sawit

Penelitian tentang sintesis dan karakterisasi selulosa asetat dari ?-selulosa fiber cake kelapa sawit ini telah dilakukan dengan menggunakan anhidrida asetat sebagai acetylating agent. Penelitian ini bertujuan untuk mendapatkan selulosa asetat dengan klasifikasi selulosa diasetat yang memiliki yield produk yang tinggi, mempelajari pengaruh variasi rasio selulosa:anhidrida asetat, waktu asetilasi, dan suhu asetilasi untuk mendapatkan selulosa asetat dengan kondisi yang optimal dari ?-selulosa fiber cake kelapa sawit. Penelitian ini menggunakan variasi rasio selulosa:anhidrida asetat (1:5; 1:10; 1:15), waktu asetilasi (0,5; 1; 1,5; 2; 2,5)jam, dan suhu asetilasi (25 dan 40) oC menghasilkan 30 sampel produk. Hasil penelitian menunjukkan bahwa selulosa asetat yang didapatkan berupa selulosa diasetat dengan bentuk padatan berupa serbuk, berwarna putih gading, dan tidak berbau serta memiliki kadar ?-selulosa sebesar 84,29 % dengan kadar air 9,16 % pada rasio selulosa:anhidrida asetat (1:10), waktu asetilasi 1,5 jam, dan suhu asetilasi 40oC dengan nilai yield produk, kadar asetil, dan derajat substitusi berturut-turut 49 %, 39,97 %, dan 2,5. Research on the synthesis and characterization of cellulose acetate from palm oil ?-cellulose fiber cake has been carried out using acetic anhydride as an acetylating agent. This study aims to obtain cellulose acetate with cellulose diacetate classification which has a high product yield, study the effect of variations in the ratio of cellulose:acetic anhydride, acetylation time, and acetylation temperature to obtain cellulose acetate with optimal conditions from palm oil ?-cellulose fiber cake. This study used variations in the ratio of cellulose:acetic anhydride (1:5; 1:10; 1:15), acetylation time (0.5; 1; 1.5; 2; 2.5) hours, and acetylation temperature (25 and 40) oC produces 30 product samples. The results showed that the cellulose acetate obtained was in the form of cellulose diacetate with a solid form in the form of powder, ivory white, and odorless and had 84.29% of a-cellulose content with 9.16% of a moisture content at the ratio of cellulose:acetic anhydride (1 :10), acetylation time 1.5 hours, and acetylation temperature 40oC with product yield, acetyl content, and degree of substitution 84.6%, 39.97%, and 2.5, respectively.

Energy Optimization and Effective Control of Reactive Distillation Process for the Production of High Purity Biodiesel

Biodiesel is a promising renewable energy option that significantly reduces the emission of greenhouse gases and other toxic byproducts. However, a major challenge in the industrial scale production of biodiesel is the desired product purity. To this end, reactive distillation (RD) processes, which involve simultaneous removal of the byproduct during the transesterification reaction, can drive the equilibrium towards high product yield. In the present study, we first optimized the heat exchange network (HEN) for a high purity RD process leading to a 34% reduction in the overall energy consumption. Further, a robust control scheme is proposed to mitigate any feed disturbance in the process that may compromise the product purity. Three rigorous case studies are performed to investigate the effect of composition control in the cascade with the temperature control of the product composition. The cascade control scheme effectively countered the disturbances and maintained the fatty acid mono-alkyl ester (FAME) purity.

The Role of Metal Ions in Fungal Organic Acid Accumulation

Organic acid accumulation is probably the best-known example of primary metabolic overflow. Both bacteria and fungi are capable of producing various organic acids in large amounts under certain conditions, but in terms of productivity-and consequently, of commercial importance-fungal platforms are unparalleled. For high product yield, chemical composition of the growth medium is crucial in providing the necessary conditions, of which the concentrations of four of the first-row transition metal elements, manganese (Mn2+), iron (Fe2+), copper (Cu2+) and zinc (Zn2+) stand out. In this paper we critically review the biological roles of these ions, the possible biochemical and physiological consequences of their influence on the accumulation of the most important mono-, di- and tricarboxylic as well as sugar acids by fungi, and the metal ion-related aspects of submerged organic acid fermentations, including the necessary instrumental analytics. Since producing conditions are associated with a cell physiology that differs strongly to what is observed under “standard” growth conditions, here we consider papers and patents only in which organic acid accumulation levels achieved at least 60% of the theoretical maximum yield, and the actual trace metal ion concentrations were verified.

Detection of Oil Palm Disease in Plantations in Krabi Province, Thailand with High Spatial Resolution Satellite Imagery

Oil palm (Elaeis guineensis) trees are an important contributor of recent economic development in Southeast Asia. The high product yield, and the consequent high profitability, has led to a widespread expansion of plantations in the greater region. However, oil palms are susceptible to diseases that can have a detrimental effect. In this study we use hyper- and multi-spectral remote sensing to detect diseased oil palm trees in Krabi province, Thailand. Proximate spectroscopic measurements were used to identify and discern differences in leaf spectral radiance; the results indicate a relatively higher radiance in visible and near-infrared for the healthy leaves in comparison to the diseased. From a total of 113 samples for which the geolocation and the hyperspectral radiance were recorded, 59 and 54 samples were healthy and diseased oil palm trees, respectively. Moreover, a WorldView-2 satellite image was used to investigate the usability of traditional vegetation indices and subsequently detecting diseased oil palm trees. The results show that the overall maximum likelihood classification accuracy is 85.98%, the Kappa coefficient 0.71 and the producer’s accuracy for healthy and diseased oil palm trees 83.33 and 78.95, respectively. We conclude that high spatial and spectral resolutions can play a vital role in monitoring diseases in oil palm plantations.

Green Solvents as an Alternative to DMF in ZIF-90 Synthesis

The use of green solvents as an alternative to dimethylformamide (DMF) in the synthesis of zeolitic imidazolate framework-90 (ZIF-90) was investigated. Two biobased aprotic dipolar solvents CyreneTM and γ-valerolactone (GVL) proved to successfully replace DMF in the synthesis at room temperature with a high product yield. While the CyreneTM—based product shows reduced porosity after activation, the use of GVL resulted in materials with preserved crystallinity and porosity after activation, without prior solvent exchange and a short treatment at 200 °C. The primary particles of 30 nm to 60 nm in all products further form agglomerates of different size and interparticle mesoporosity, depending on the type and molar ratios of solvents used.

PARAMETERS INFLUENCE INVESTIGATION OF THE BIODIESEL FUEL SYNTHESIS BY THE TRANSESTERIFICATION REACTION ON THE PRODUCT YIELD AND KEY CHARACTERISTICS

The paper investigated the parameters influence (reaction time, reaction temperature, NaOH catalyst concentration, oil: ethanol molar ratio) of biodiesel fuel synthesis by the transesterification reaction of sunflower oil on the product yield and key characteristics. It was established that the optimal synthesis parameters for maximizing the target product yield are the following: catalyst weight – 2.0 % of oil weight; reaction time – 1.0 hour; molar ratio oil: ethanol – 1 : 6; temperature – 45 °C. Also, from the standpoint of the biodiesel fuel physicochemical properties, the following synthesis parameters are optimal : catalyst weight – 2.0 % of oil weight; reaction time – 1.0 hour; molar ratio oil: ethanol – 1 : 12; temperature – 45 °С. It should be noted that from the stand point of using biodiesel as a commercial diesel fuels blend component, high product yield is most important. The bio-components involvement in the blend diesel fuel production will result in an average increase of the fuel pool by 20%.

Xylitol production from non-detoxified Napiergrass hydrolysate using a recombinant flocculating yeast strain

Xylose derived from lignocellulose can be utilized to produce ethanol and other high-value chemicals, such as xylitol. The xylitol production through fermentation of lignocellulosic hydrolysate by microorganisms offers advantages of high product yield, high selectivity, and efficacy in mild conditions. In this study, non-detoxified hemicellulose hydrolysate from napiergrass was used for xylitol production by a recombinant flocculating strain of Saccharomyces cerevisiae. An optimization study was conducted with the strain at 35 °C. A promising xylitol yield of 0.96 g/g xylose with no addition of glucose required during the fermentation process, which suggests an extensive potential improvement for the economics of lignocellulosic xylitol production.

Effect of Drying Temperature of Small Scale Spray Dryer on Physical Properties of Coffee Powder

Nowadays, coffee has become one of the most favorable commodities for beverages, flavoring as well as for cosmetic industries. In Indonesia, coffee becomes more popular, especially among youngsters. In this study, the spray drying process was evaluated, giving the potential of how simple spray dryer can help local farmers of Indonesia to produce their coffee powders. One small scale of spray dryer was constructed with the total dimensions of 2.85 x 0.64 for length x width, with a height of 2.32 m. The spray dryer was equipped with a digital thermo regulator, the pneumatic nozzle system, and 4 finned heaters with the power of 2700 watt for each. The spray drying constructed was revealed to be able to produce coffee powders with fine quality. The inlet temperature of the drying chamber, as well as the initial Brix content of feed solution, were proven to affect the physical properties of powder produced such as moisture content, product yield, and solubility. The final moisture content of powders was ranged from 3 - 7% db, with the high product yield of the drying process, which could reach up to 70%.

Encapsulation of Vitamins A and E as Spray-Dried Additives for the Feed Industry

Encapsulated fat-soluble powders containing vitamin A (VA) and E (VE) were prepared as a feasible additive for extruded feed products. The effect of the encapsulating agents (Capsul-CAP®, sodium caseinate-SC) in combination with Tween 80 (TW) as an emulsifier and maltodextrin (MD) as a wall material on the physicochemical properties of emulsions and powders was evaluated. First, nanoemulsions containing MD:CAP:TW:VA/VE and MD:SC:TW:VA/VE were prepared and characterized. Then, powders were obtained by means of spray-drying and analyzed in terms of the product yield, encapsulation efficiency, moisture content, porosity, surface morphology, chemical structure, and thermal properties and thermo-oxidative/thermal stability. Results showed that although nanoemulsions were obtained for all the compositions, homogeneous microcapsules were found after the drying process. High product yield and encapsulation efficiency were obtained, and the presence of the vitamins was corroborated. The characteristics of the powders were mainly influenced by the encapsulating agent used and also by the type of vitamin. In general, the microcapsules remained thermally stable up to 170 °C and, therefore, the proposed encapsulation systems for vitamins A and E were suitable for the preparation of additives for the feed manufacturing through the extrusion process.