Study of flavonoids in aqueous spinach extract using positive electrospray ionisation tandem quadrupole mass spectrometry

The presence of three flavonols (quercetin, kaempferol, myricetin) and two flavones (apigenin, luteolin) were investigated in the extract of fresh spinach leaves. Aqueous spinach extracts were prepared with a leaf/water ratio of 1:2 at 80 °C for 30 min stirring. Ferric ammonium sulphate method was used for measuring total polyphenols in the extracts and expressed as catechins and tannic acid equivalents. The flavonoids glycosides in the extract were hydrolysed to their aglycons with 1.2 M HCl in boiling 50% water methanol solution. The resulting aglycons were identified and quantified by a C18 reverse phase high-performance liquid chromatography (RP-HPLC). Furthermore, the results were confirmed by HPLC coupled to an electrospray ionisation tandem triple-quadrupole mass spectrometer ESI-MS performing low-energy collision induced dissociation (CID-MS/MS) in the collision cell (HPLC-ESI-MS/MS). Analyses were made in the multiple reaction monitory (MRM) mode. Results showed that total polyphenols contents in fresh spinach leaves were 270 mg kg⁻¹ and 390 mg kg⁻¹ as tannic acid and catechin equivalents, respectively, in which, major flavonoids aglycons were apigenin (170 mg kg⁻¹), quercetin (50 mg kg⁻¹) and kaempferol (30 mg kg⁻¹).     

A study of a water-reducing agent from cashew nutshell liquid

The water-reducing agent better known as superplasticizer is a recent development. A number of base materials have been used for the development of such water-reducing agents which can act better than ordinary plasticizers in concrete. The sulphonated salts of melamine, napthalene, lignin, hydroxycarboxylic acids and hydroxylated polymers are some typical compounds. Recently cashew nutshell liquid obtained from a natural product waste as a thick black phenolic compound has been converted into a water-reducing agent. This paper describes the results obtained on its effectiveness in influencing the rheological properties of flow, viscosity, particle size distribution, etc, of cement particles in hydrating cements and the water-reducing capabilities in cement mortars and concretes.     

An investigation into design and manufacturing of mechanical conveyors systems for food processing

This paper presents the results of a research investigation undertaken to develop methodologies and techniques that will reduce the cost and time of the design, manufacturing and assembly of mechanical conveyor systems used in the food and beverage industry. The improved methodology for design and production of conveyor components is based on the minimisation of materials, parts and costs, using the rules of design for manufacture and design for assembly. Results obtained on a test conveyor system verify the benefits of using the improved techniques. The overall material cost was reduced by 19% and the overall assembly cost was reduced by 20% compared to conventional methods.     

The root cause of black pad failure of solder joints with electroless Ni/Immersion gold plating

This paper reports on a study of the reaction of solder with the electrolessnickel with immersion gold (ENIG) plating system, and the resulting interfacial structures. Aforcused-ion beam (FIB) was used to polish the cross sections to reveal details of the microstructure of the ENIG-plated pad with and without soldering. High-speed pull testing of solder joints was performed to expose the pad surface. Results of scanning-electron microscopy/energy-dispersive x-ray analysis of the cross sections and fractured pad surfaces support the suggestion that black pad is the result of galvanic hyper-corosion of the plated electroless nickel by the gold plating bath. Criteria are proposed for diagnosing black pad of ENIG plating.     

DOE applied to multi-response optimisation study on performance,combustion and emission characteristics of a VCR diesel engine

There are various parameters which may influence the IC engine performance. The trial and error method is a technique used to identify the best parameters. However, this method demands extensive experimental work and results in a great waste of time and resources. Thus, the design of experiments (DOEs) developed by Taguchi is employed. The multi-responses which need to be maximised are brake thermal efficiency, mechanical efficiency, cylinder pressure and cumulative heat release rate, whereas the responses which are to be minimised are specific fuel consumption, oxides of nitrogen and carbon monoxide. In the present study, an optimised DOE(L9) orthogonal array based on the Taguchi statistical method was formulated and a series of experiments were conducted under controlled supervision by considering three different injection operating pressures (IOPs) (200, 220 and 240 bar) and three different compression ratios (CRs) (16.5, 17.5 and 18.5). The main objective of this paper is to find the best suited IOP and CR values which obtain higher performance, better combustion and lower emissions.     

Optimization of fused deposition modeling process parameters:a review of current research and future prospects

Fused deposition modeling(FDM) is one of the most popular additive manufacturing technologies for various engineering applications.FDM process has been introduced commercially in early 1990 s by Stratasys Inc.,USA.The quality of FDM processed parts mainly depends on careful selection of process variables.Thus,identification of the FDM process parameters that significantly affect the quality of FDM processed parts is important.In recent years,researchers have explored a number of ways to improve the mechanical properties and part quality using various experimental design techniques and concepts.This article aims to review the research carried out so far in determining and optimizing the process parameters of the FDM process.Several statistical designs of experiments and optimization techniques used for the determination of optimum process parameters have been examined.The trends for future FDM research in this area are described.     

Bimetallic dies with direct metal-deposited steel on Moldmax for high-pressure die casting application

In high-pressure die casting, cooling time greatly affects the total cycle time. As thermal conductivity is the main governing factor, a higher thermal conductive die material allows faster extraction of heat from the casting, thus resulting in shorter cycle time and higher productivity. This paper presents a novel approach to replace a conventional steel die by a bimetallic die made of Moldmax copper alloy coated with a protective layer of steel using laser cladding technology, direct metal deposition on the cavity surface for high-pressure die casting of aluminum alloys. Study includes the investigation of suitable steel layer thickness on Moldmax substrate in terms of porosity, hardness, presence of copper content, and copper particle. Results obtained from the scanning electron microscope and energy dispersive spectroscopy display a metallurgicallly sound and fully dense steel layer on copper alloy. Results of finite element heat transfer analysis also show that bimetallic die offers superior thermal performance compared with monolithic steel die.