We study a periodic-review production/inventory control problem where both the supply of raw material and demand for the finished product are exogenous and random, the raw material can be stored for future use, can be purchased from or sold to an outside market. We study both the lost sales and backlogging cases under both strict convex and linear raw material purchasing/selling costs. Convexit...

Oil palm ash (OPA), a bio-agricultural waste from oil palm mills, was subjected to high-energy ball milling for 30 h and was converted into a nano-structured material. The nano-structured OPA was characterized for its particle size and crystallinity index by using Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) analysis. The crystallite size obtained from TEM and XRD was foun...

Slurries of rice-straw cellulose (obtained by delignification and removal of hemicelluloses from the powdered raw material) were subjected to ultrasonic waves at different intensities for various times (constant temperature). Susceptibility of the samples to cellulose-hydrolysis increased initially with pretreatment time, reaching a maximum or a constant level thereafter. Maximum glucose yi...

Magnesium raw materials are available worldwide. In the free market, the prevailing price of primary magnesium metal determines which combinations of raw material/extraction method are economically viable. Over the last 20 years, China’s exports benefited from favourable currency exchange rates and positive relations with the USA and European countries. Lax environmental regulations, in conjunc...

Micro-manufacturing emerged in the last years as a new engineering area with the potential of increasing peoples’ quality of life through the production of innovative micro-devices to be used, for example, in the biomedical, micro-electronics or telecommunication sectors. The possibility to decrease the energy consumption makes the micro-manufacturing extremely appealing in terms of environment...

thermal decomposition of two coal samples obtained from top seam sibi (tss) and sore range quetta (srq) coal fields in their raw and acid washed forms were carried out in an open type tubular pyrolyzer coupled to a gas chromatograph with fid. elemental analyses were carried out with scanning electron microscope-energy dispersive x-rays (sem-edx) analyzer. effect of inherent mineral contents on ...

The demand for herbal raw material has increased tremendously due to renewed interest in plant-based medicines, especially in developed countries. This has led to the indiscriminate cutting and collection of medicinal plants from natural resources resulting in depletion of natural resources and in some cases extinction of species. In the recent past, aseptically grown raw material and cell cult...