Microstructural Characterization of Fried Potato Disks Using X‐Ray Micro Computed Tomography

Microstructural properties play a key role to affect oil uptake and product quality during frying of foods. The objective of this study was to observe the complex microstructural changes and mass transfer mechanisms in potato disks during frying. The potato disks of 1.65 mm thickness were fried at 190 °C for 0, 20, 40, 60, and 80 s. X‐ray micro‐computed tomography (CT) was used for 3‐dimensional (3D) imaging of microstructure of porous potato disks. Total porosity, pore size distribution, oil content, and air content of potato disks were calculated from resulting 3D data sets. Oil and air content measured by analysis of micro‐CT images followed trends similar to Soxtec and gas pycnometry methods, respectively. Image analysis showed a significant change in pore size distribution as a function of frying time. Frying time was also observed to have an effect on tortuosity, which is an important microstructural fluid transport property. Tortuosity was measured by path length ratio method from 3D data sets obtained from image analysis. A linear inverse relationship was observed between porosity and tortuosity where tortuosity decreased with the increase of porosity. It was also observed that during frying, oil content increased with the decrease of tortuosity. This phenomenon indicated that the lower tortuosity created a less complicated and sinuous path, thus resulting in less resistance to oil penetration. Micro‐CT technique can serve as an effective tool for elucidating microstructure of fried foods, and can provide complementary information to conventional lab techniques.     

Significant physical attributes affecting quality of Indian black (CTC) tea

In this research work, an attempt was made to discriminate different grades of black crush-tear-curl (CTC) tea based upon their physical attributes such as color of brewed liquor, texture, size and shape of the tea granules obtained by machine vision technique. The principal component analysis (PCA) was applied over two types of data. First, tea samples with seven different quality grades but same mechanical grading and second, samples with same quality grade but nine different mechanical grades (Brokens, Fannings and Dust) were considered for analysis, respectively. The results of PCA showed that best discrimination (100%) in both types of data was given by color attributes only. Correlations among tea samples and physical attributes were determined. Based upon these results it may be concluded that color only attributes are the most significant and sufficient for quantification of tea quality whereas other physical attributes contribute so little to quality estimation that they may be ignored.     

Catalytic action of gold and copper crystals in the growth of carbon nanotubes

Multi-wall carbon nanotubes are grown in a chemical vapor deposition process by using bulk gold and copper substrates as catalysts. Nanotube growth starts from a nanometer-sized roughness on the metal surfaces and occurs in a mechanism where the catalyst particle is either at the tip (Au) or root (Cu) of the growing nanotube. Whereas Au leads to nanotubes with good structural perfection, nanotubes grown from Cu show a higher density of defects. High-resolution transmission electron microscopy shows the bonding between Au and carbon at the metal-nanotube interface whereas no bonds between Cu and carbon occur. Highly mobile Au or Cu atoms adsorb at the growing edge of a carbon nanotube from where diffusion along the nanotube wall can lead to the formation of Au or Cu nanowires inside the central hollow of carbon nanotubes.     

Investigations of lanthanum doping on magnetic properties of nano cobalt ferrites

The magnetic properties of nano-crystallite cobalt lanthanum ferrite (CoLa_xFe_2-x O₄) with varied quantities of lanthanum (x = 0, 0.1, 0.15, 0.2, 0.25, 0.3) prepared by co-precipitation method have been studied by vibrating sample magnetometer (VSM) and LCR meter. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the size, structure, and morphology of the ferrite samples. The average crystallite size varied from 17.83 nm to 49.99 nm. All the samples, although, in nano range, show significant hysteresis. The saturation magnetization (M_s) values decreased from 60.57 emu/g to 30.15 emu/g. The remanence (M_R) fell from 10.85 emu/g to 6.39 emu/g. Doping with lanthanum La³⁺ ions modulates significantly the magnetic properties of cobalt spinel ferrites without sacrificing the ferromagnetic character.     

A two-scale model for discrete cell gravure roll coating

A two-dimensional model for predicting the fluid pickout and coated film thickness characteristics of a discrete cell direct gravure roll coater operating in reverse mode is derived. A novel multiscale approach is adopted for this purpose and the resulting equations solved numerically for inertia-less flow conditions. A system of stiff ordinary differential equations is found to be sufficient to capture the major gross flow features, while at the cell level the analysis is based on a finite element solution of the momentum and continuity equations. It represents the first such predictive model of its kind, with particular interest placed on the nature of both the pressure distribution and web-to-roll gap profile spanning the coating bead. The effect of key operating parameters, web-to-roll speed ratio, web-tension, wrap-angle, capillary number and cell-geometry, on the degree of fluid pickout from gravure cells and the coated film thickness is explored. Although an idealised model, the trends observed show qualitative agreement with existing experimental data collected on a small-scale gravure coating rig and point the way forward to the eventual formulation of a full three-dimensional predictive model of the process.     

Single Step Synthesis of Nitro‐Functionalized Hydroxyl‐Terminated Polybutadiene

The paper reports the energization of Hydroxyl‐Terminated Polybutadiene (HTPB) by functionalizing explosophore  NO₂ over the HTPB backbone, resulting in the formation of conjugated nitro‐alkene derivative of HTPB. A convenient, inexpensive and efficient “one pot” procedure of synthesizing Nitro‐Functionalized Hydroxyl‐Terminated Polybutadiene (Nitro‐HTPB) is reported. The reaction was carried out with sodium nitrite and iodine. To retain the unique physico‐chemical properties of HTPB, functionalization by  NO₂ group was restricted to 10 to 15 % of double bonds. The Nitro‐HTPB was characterized by FTIR, ¹H NMR, VPO, DSC, TGA etc. The polymer has shown good thermal stability for practical applications. The kinetic parameters for the decomposition of Nitro‐HTPB at 150–300 °C were obtained from non‐isothermal DSC data.     

Placental Complement Activation in Fetal and Neonatal Alloimmune Thrombocytopenia: An Observational Study

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a disease that causes thrombocytopenia and a risk of bleeding in the (unborn) child that result from maternal alloantibodies directed against fetal, paternally inherited, human platelet antigens (HPA). It is hypothesized that these alloantibodies can also bind to the placenta, causing placental damage. This study aims to explore signs of antibody-mediated placental damage in FNAIT. We performed a retrospective study that included pregnant women, their newborns, and placentas. It comprised 23 FNAIT cases, of which nine were newly diagnosed (14 samples) and 14 were antenatally treated with intravenous immune globulins (IVIg) (21 samples), and 20 controls, of which 10 had anti-HLA-class I antibodies. Clinical information was collected from medical records. Placental samples were stained for complement activation markers (C1q, C4d, SC5b-9, and mannose-binding lectin) using immunohistochemistry. Histopathology was examined according to the Amsterdam criteria. A higher degree of C4d deposition was present in the newly diagnosed FNAIT cases (10/14 samples), as compared to the IVIg-treated FNAIT cases (2/21 samples, p = 0.002) and anti-HLA-negative controls (3/20 samples, p = 0.006). A histopathological examination showed delayed maturation in four (44%) placentas in the newly diagnosed FNAIT cases, five (36%) in the IVIg-treated FNAIT cases, and one in the controls (NS). C4d deposition at the syncytiotrophoblast was present in combination with low-grade villitis of unknown etiology in three newly diagnosed FNAIT cases that were born SGA. We conclude that a higher degree of classical pathway-induced complement activation is present in placentas from pregnancies with untreated FNAIT. This may affect placental function and fetal growth.     

Temporary and Permanent Viscosity Loss Correlated to Hydraulic System Performance

ABSTRACT

Straight- and multigrade fluids were evaluated in a hydraulic dynamometer that incorporated a pressure-compensated axial piston pump and a fixed displacement axial piston motor. Pump, motor, pressure compensator, and directional control valve internal flow losses were determined under various conditions of pressure, speed, and temperature. Fluid samples were collected before and at various times during the dynamometer experiments, and viscosity measurements were performed to probe for correlations between viscosity, operating time, and system leakage flow losses. The low shear rate viscosities of the multigrade fluids decreased linearly throughout the duration of testing due to polymer degradation. However, system flow losses did not exhibit a statistically significant increase as the multigrade fluids sheared down. The fluids were also characterized by their permanent viscosity loss produced in sonic shear and tapered bearing tests and by their temporary shear thinning measured in an ultra-high-shear viscometer at several temperatures. The effects of these viscous properties were analyzed using an empirical model to identify which measures of viscosity were most correlated with flow loss. The results suggested that the relative contributions of temporary and permanent viscosity loss change as the fluid is used. Further, analysis of torque loss and input power revealed that input power and losses are more useful indicators of the effect of fluids on hydraulic system performance than pump efficiency.     

Study of additive‐additive interactions in a lubricant system by NMR,ESCA, and thermal techniques

Engine oil lubricants are formulated with a variety of additive components at different dosages to obtain the desired physico‐chemical characteristics. Antiwear, friction modification/energy efficiency, dispersancy, and detergency properties are normally achieved by the use of zinc dialkyldithiophosphate (ZDDP), molybdenum dithiocarbamate (MoDTC) and ashless alkyl phosphorodithioate, polyisobutylene succinimide (PIBS), and metal sulphonates / phenates, respectively. It has been reported that these additives interact with each other and affect the overall performance of a lubricant system. The additive‐additive interactions have been studied by nuclear magnetic resonance (NMR) and infrared spectroscopic techniques, where attention has been mainly focused on the ZDDP‐PIBS additive system in the presence or absence of other additives. The results have been used to relate the synergistic or antagonistic effects of such interactions to the overall performance of a lubricant. Recently, MoDTC has found wider application in lubricants as a friction modifier and energy‐efficient additive. However, no studies of the additive‐additive interactions of the PIBS‐MoDTC‐ZDDP additive system using analytical techniques have been reported. The present paper covers the fundamental and mechanistic aspects of additive‐additive interactions of ZDDP, MoDTC, PIBS, and sulphonate / phenate additives present in a lubricant system as studied by ³¹P NMR, electron spectroscopy for chemical analysis (ESCA), and thermogravimetric analysis (TGA) techniques. ESCA, which is a surface analytical technique, has been used to provide basic evidence for the formation of various complexes through interactions occurring in the electronic binding energies of orbitals of various atoms of the additives. The ESCA studies have also revealed the actual atomic sites of interaction between the additives responsible for the formation of adducts or complexes. The differential scanning calorimetry profiles of blends have verified the interactions among the additives and shown that the stability of the additive system is quite different from that of the additives alone. The shifts in the ³¹P NMR signals, the changes in the binding energies of the s, p, and d orbitals of additive elements, and the multistage decomposition profiles in the TGA thermograms of interacting systems due to complexion and adduct formation have enabled a mechanism of interaction to be proposed.