Optimization of Procedures for In-Line Extraction of Lipids and Polyphenols from Grape Seeds

Grape seeds (Vitis vinifera L.), a type of raw material containing around 20 % (w/w) of lipids and 20 % (w/w) of phenolic compounds in dry weight, are the main by-products in wine industry. In this work, water and hydroalcoholic mixtures have been first investigated to obtain the optimal solvent for further extractions. Polyphenols and lipids were then extracted by three combined extraction procedures to compare their effectiveness so that the optimal procedure was determined. The results showed that the best yield was achieved by the in-line combination of maceration before grinding and followed by Soxhlet extraction using aqueous ethanol (ethanol/water, 80:20 v/v) at 80 °C.     

A new assumed strain solid-shell formulation “SHB6” for the six-node prismatic finite element

This paper presents the development of a new prismatic solid-shell finite element, denoted SHB6, obtained using a purely three-dimensional approach. This element has six nodes with displacements as the only degrees of freedom, and only requires two integration points distributed along a preferential direction, designated as the “thickness”. Although geometrically three-dimensional, this element can be conveniently used to model thin structures while taking into account the various phenomena occurring across the thickness. A reduced integration scheme and specific projections of the strains are introduced, based on the assumed-strain method, in order to improve performance and to eliminate most locking effects. It is first shown that the adopted in-plane reduced integration does not generate “hourglass” modes, but the resulting SHB6 element exhibits some shear and thickness-type locking. This is common in linear triangular elements, in which the strain is constant. The paper details the formulation of this element and illustrates its capabilities through a set of various benchmark problems commonly used in the literature. In particular, it is shown that this new element plays a useful role as a complement to the SHB8PS hexahedral element, which enables one to mesh arbitrary geometries. Examples using both SHB6 and SHB8PS elements demonstrate the advantage of mixing these two solid-shell elements.     

A First Course in the Theory of Linear Statistical Models

We reduce the dimension of the integration of the computation of the cumulative distribution function of version X of the half-normal plot. This speeds computation of the critical values.     

Characterisation and comparison of the micromixing efficiency in torus and batch stirred reactors

The mixing at a molecular scale (micromixing) plays an important role on selectivity, yield and quality of final products of a large range of competing fast chemical reactions. In this study, we have compared, by the use of iodide–iodate reaction tests, the micromixing in two reactors, the first one is the standard batch stirred reactor and the second is the torus reactor. Various conditions of agitation and feed locations were used for this study. A comparative analysis of the micromixedness ratio (α) in the two reactors was carried out on the basis of the local rate of specific energy dissipation.     

Failure Analysis of Howell-Bunger Valve Using Finite Element Method

Fixed-cone (Howell-Bunger) valves have been in wide use for many years for flow control. These valves may face different types of damages and failures due to vibrational stresses during operation. In this study, a number of modal analyses of a Howell-Bunger (DN: 1000 mm) valve were conducted using the Finite Element Method (FEM), and its natural frequencies with vibrational mode shapes in five cases including fully opened, 20-, 40-, and 80%-opening conditions were determined; subsequently, the dimensionless coefficient “Mercer” was obtained for the valve. The result showed that the operating point of the valve is the flow rate of 16 m³/s and valve opening degree of 40%; in this case, due to reinforcement resulting from moving shell, the structure strength against vibration increases, and as a result, natural frequency increases as well.     

Pareto optimization of a five-degree of freedom vehicle vibration model using a multi-objective uniform-diversity genetic algorithm (MUGA)

In this paper, a new multi-objective uniform-diversity genetic algorithm (MUGA) with a diversity preserving mechanism called the ε-elimination algorithm is used for Pareto optimization of a five-degree of freedom vehicle vibration model considering the five conflicting functions simultaneously. The important conflicting objective functions that have been considered in this work are, namely, seat acceleration, forward tire velocity, rear tire velocity, relative displacement between sprung mass and forward tire and relative displacement between sprung mass and rear tire. Further, different pairs of these objective functions have also been selected for 2-objective optimization processes. The comparison of the obtained results with those in the literature demonstrates the superiority of the results of this work. It is shown that the results of 5-objective optimization include those of 2-objective optimization and, therefore, provide more choices for optimal design of a vehicle vibration model.     

How implementation of Quality by Design and advances in Biochemical Engineering are enabling efficient bioprocess development and manufacture

In recent years, Quality by Design (QbD) has gained significant prominence in the pharmaceutical industry as an efficient way of designing and controlling processes used to make therapeutic products. At its heart, QbD seeks to identify an operating envelope within which production consistently satisfies a target product quality profile and thereby achieves the desired level of safety and efficacy. Such an approach is assisted by a range of Biochemical Engineering techniques which increase process and product understanding. This perspective describes how the principles of Quality by Design and developments in the field of Biochemical Engineering are providing the pharmaceutical sector with a toolbox of methods that enable efficient bioprocess development and manufacture. Copyright © 2011 Society of Chemical Industry     

Serum Oxidized-LDL is Associated with Diabetes Duration Independent of Maintaining Optimized Levels of LDL-Cholesterol

Oxidized low-density lipoprotein (ox-LDL) plays a key role in the progression of atherosclerosis and diabetes complications. The aim of this study was first, to evaluate the association between ox-LDL and diabetes duration, and second, to examine serum level of ox-LDL in patients with prolonged diabetes and a desirable LDL-cholesterol level. A total of 36 type-2 diabetic patients with a diabetes duration of more than 5 years, 36 newly diagnosed diabetic patients, and 36 age-, sex- and BMI-matched healthy participants were recruited. Healthy participants and newly diagnosed patients were not receiving any treatment. All patients with prolonged diabetes had desirable LDL-cholesterol levels (<100 mg/dL), according to the adult treatment panel-III guidelines. While LDL-cholesterol was significantly lower in patients with diabetes duration >5 years, in comparison to newly diagnosed patients (P < 0.01), ox-LDL was significantly higher in patients with prolonged diabetes (P < 0.001). The ox-LDL-to-LDL ratio was dramatically higher in patients with diabetes duration >5 years in comparison to newly diagnosed patients and healthy participants (P < 0.001). Ox-LDL was significantly associated with diabetes duration (r = 0.519, P = 0.001). In multivariate analysis, this association remained significant (β = 0.501, P = 0.003) after adjustment for potential confounders. In conclusion, this study showed that the serum ox-LDL level increases with the length of diabetes, even though the patients’ LDL-cholesterol level is maintained at a desirable level. Our findings highlight that possibly more attention should be focused on markers of oxidative stress in the management of lipids in diabetic patients.     

Geographical Differentiation of Rosemary Based on GC/MS and Fast HPLC Analyses

This paper focuses on characterization of target compounds of rosemary from 16 regions of Algeria in order to highlight the correlation between the samples composition and their origin. Essential oil was determined using gas chromatography coupled to mass spectrometry. Phenolic compounds were analysed using high performance liquid chromatography based on two monolithic columns (HPLC-DAD). The analyses revealed that hydrodistilled essential oils content ranged from 0.33 to 1.47 %; the maximum amounts were observed in the National Institute of Agronomy. A total of 25 components accounting for 88.11–99.80 % of the total essential oil, according regions were identified. α-Pinene (20.13–72.58 %) and camphor (6.64–36.44 %) were identified as the main constituents on oils. Two chemotypes for this plant were proposed. The main antioxidants compounds (carnosol, rosmarinic and carnosic acid) in rosemary were determined at a concentration ranging from 0.27 to 2.49 % for rosmarinic acid, 0.01 to 1.77 % for carnosic acid and 0.17 to 0.94 % for carnosol, according to regions.