Formation of Furan Fatty Alkyl Esters from their Bis‐Epoxide Fatty Esters

Reactions of epoxidized alkyl soyate with four different alcohols: ethanol, isopropyl alcohol, 2‐ethylhexanol, benzyl alcohol, in the presence of Brønsted acid catalyst, were investigated. Products, not reported in prior studies of similar reactions, were found. These were furan fatty acid alkyl esters (FFE, mixture of alkyl 8‐(5‐hexyl‐2‐furyl) octanoate and alkyl 9‐(5‐pentyl‐2‐furyl)nonanoate) which were unambiguously identified by means of GC–MS and two‐dimensional NMR. Evidence suggests that the FFE are formed by an acid‐catalyzed rearrangement of the epoxidized linoleates. The FFE were formed in presence of all four alcohols tested and in the presence of either sulfuric acid or Amberlyst 15 catalyst. Yields of up to 13 %, as quantified by GC and NMR spectroscopies, were observed.     

Techno-economic analysis of photovoltaic pumping system for rural water supply in Ethiopia

The diesel-driven water pumping systems have a great impact on rural water supply in Ethiopia in past decades due to the lack of access to grid electricity and associated capital intensive nature of grid expansion to rural areas. However, the requirement of diesel generator for frequent maintenance and soaring fuel cost encourages the government and concerned bodies such as NGO to go for most reliable and cost-effective alternatives. In this paper, direct coupled photovoltaic (PV) pumping system has been designed for hypothetical rural village in southern region near Arba Minch (latitude 6.02^″N, Longitude 37.54^″E) to show techno-economic feasibility of the technology. The result shows that direct coupled PV pumping system is cost-effective in terms of life cycle cost and technologically feasible for rural water supply by virtue of its very low running cost and high reliability of the component and the system as a whole.     

Classification of rose flowers based on Fourier descriptors and color moments

Multimedia Tools and Applications - In this paper, a rose-flower variety classification scheme, using color and shape features is presented. The first three statistical moments of the R, G, and B...     

Biobased Polyalphaolefin Base Oil: Chemical,Physical, and Tribological Properties

The properties of a biobased polyalphaolefin with a viscosity of 40 cSt at 100 °C (BPAO-40) were investigated relative to a commercial petroleum-based PAO of similar viscosity at 100 °C (PAO-40). BPAO-40 was synthesized by oligomerization of a mixture of alpha olefins, with and without terminal methyl esters. These olefins were obtained from vegetable oils via a biorefinery process. In contrast to BPAO-40, commercial PAO-40 is synthesized only from non-functionalized alpha olefins. Thus, BPAO-40 is not only biobased, but also has a unique chemical structure, which makes it a functionalized PAO. The effect of chemical structure (presence or lack of methyl ester functionalization) on chemical, physical, and tribological properties of these two base oils was investigated. The investigation showed that, relative to the commercial non-functionalized PAO-40, the functionalized BPAO-40 displayed the following properties: higher density at 40–100 °C, lower number average molecular weight, higher polydispersity index, higher viscosity index, lower oxidation stability (pressurized differential scanning calorimetry), higher total acid number, higher free fatty acid, lower four-ball anti-wear coefficient of friction (COF) and lower wear scar diameter (WSD), higher elastohydrodynamic (EHD) lubricant film thickness under boundary conditions (low speeds and high temperature), lower EHD traction coefficient at 40 and 100 °C, similar pressure–viscosity coefficient, lower COF, lower WSD, and higher relative film thickness on a high-frequency reciprocating rig tribometer under boundary conditions (low speeds).     

Film-Forming Properties of Blends of High-Oleic Sunflower Oil with Polyalkyl Glycol

The viscosity, density, and elastohydrodynamic film thicknesses of oil-soluble polyalkyl glycols (PAG), high oleic sunflower oil (HOSuO), and their 50/50 (wt.%) blends were investigated. The viscosity and density of the blends were found to be predictable from the corresponding neat oil properties using simple mixing rules. Pressure–viscosity coefficients (PVC) of HOSuO, the two PAGs, and the two 50?wt% HOSuO/50?wt% PAG blends were calculated from measured film thickness data using the Hamrock-Dowson method and compared to values estimated from literature data. Literature pressure-density and viscosity-temperature data for oils with high-oleic acid group content were analyzed using the Tait and Casalini et al. models. Viscosity versus pressure data obtained from these analyses was used to calculate PVC using the Barus and Bair et al. models. The PVC values calculated from the literature data following this procedure showed reasonable agreement with that from film thickness data from this work.     

Newly identified mutations at the CSN1S1 gene in Ethiopian goats affect casein content and coagulation properties of their milk

Very high casein content and good coagulation properties previously observed in some Ethiopian goat breeds led to investigating the α_s1-casein (CSN1S1) gene in these breeds. Selected regions of the CSN1S1 gene were sequenced in 115 goats from 5 breeds (2 indigenous: Arsi-Bale and Somali, 1 exotic: Boer, and 2 crossbreeds: Boer × Arsi-Bale and Boer × Somali). The DNA analysis resulted in 35 new mutations: 3 in exons, 3 in the 5′ untranslated region (UTR), and 29 in the introns. The mutations in exons that resulted in an amino acid shift were then picked to evaluate their influence on individual casein content (α_s1-, α_s2-, β-, and κ-CN), micellar size, and coagulation properties in the milk from the 5 goat breeds. A mutation at nucleotide 10657 (exon 10) involved a transversion: CAG→CCG, resulting in an amino acid exchange Gln₇₇→Pro_77. This mutation was associated with the indigenous breeds only. Two new mutations, at nucleotide 6072 (exon 4) and 12165 (exon 12), revealed synonymous transitions: GTC→GTT in Val₁₅ and AGA→AGG in Arg₁₀₀ of the mature protein. Transitions G→A and C→T at nucleotides 1374 and 1866, respectively, occurred in the 5′ UTR, whereas the third mutation involved a transversion T→G at nucleotide location 1592. The goats were grouped into homozygote new (CC), homozygote reference (AA), and heterozygote (CA) based on the nucleotide that involved the transversion. The content of α_s1-CN (15.32 g/kg) in milk samples of goats homozygous (CC) for this newly identified mutation, Gln₇₇→Pro₇₇ was significantly higher than in milks of heterozygous (CA; 9.05 g/kg) and reference (AA; 7.61 g/kg) genotype animals. The α_s2-, β-, and κ-CN contents showed a similar pattern. Milk from goats with a homozygous new mutation had significantly lower micellar size. Milk from both homozygote and heterozygote new-mutation goats had significantly shorter coagulation rate and stronger gel than the reference genotype. Except the transversion, the sequence corresponded to allele A and presumably derived from it. Therefore, this allele is denoted by A₃. All goats from the reference genotype (AA) were homozygous for the allele at nucleotide position 1374 and 1866, whereas all mutations in the 5′ UTR existed in a heterozygous form in both heterozygous (CA) and the new mutation (CC) genotype. The newly identified mutation (CC) detected in some of the goat breeds is, therefore, important in selection for genetic improvement and high-quality milk for the emerging goat cheese-producing industries. The finding will also benefit farmers raising these goat breeds due to the increased selling price of goats. Further studies should investigate the effect of this amino acid exchange on the secondary and tertiary structure of the α_s1-CN molecule and on the susceptibility of peptide hydrolysis by digestive enzymes.     

THD analysis for finite slider bearing with roughness: special reference to load generation in parallel sliders

This paper analyses the thermal and roughness effects on different characteristics of finite rough tilted pad slider bearings. The roughness is assumed to be stochastic, Gaussian randomly distributed. Density and viscosity are assumed to be temperature dependent. In this study, two models of one-dimensional roughness, longitudinal and transverse, are considered. The irregular domain due to roughness is mapped to a regular domain so that the numerical method can be easily applied. The modified Reynolds equation, momentum equation, continuity equation and energy equation are coupled and solved using the finite difference method to yield various bearing characteristics. It is observed that for nonparallel slider bearing the load carrying capacity due to the combined effect is less than the load capacity due to the roughness effect for both longitudinal and transverse roughness models. However, in case of a parallel pad slider bearing, the reverse is true, though the load capacity is not significant. It is also observed that the load carrying capacity due to the combined effect is larger than the load carrying capacity due to the thermal effect for both roughness models.     

Friction properties of chemically modified starch

Starches of varying chemical structures were esterified with anhydrides, formulated into dry film lubricants with the addition of canola oil, and its friction properties investigated. In the absence of canola, chemically modified starch displayed a very high coefficient of friction (COF). Addition of canola resulted in a sharp decrease in COF, which decreased with increasing [canola] until it attained a minimum and constant value that was independent of the further increase in [canola]. This observation was attributed to the adsorption of the canola oil onto starch due to H‐bonding between the ester groups of the canola triglycerides and the free hydroxyl groups of starch. Analysis of the [canola] vs COF data using the Langmuir adsorption model showed stronger adsorption of canola to modified starch with a lower degree of substitution (DS). This was attributed to the availability of more free hydroxyl group adsorption sites on starches with lower DS than those with higher DS. Copyright © 2008 John Wiley & Sons, Ltd.