This work aimed to produce hydrogen (H₂) simultaneously with pollutant removal from biodiesel wastewater by photocatalytic oxidation using a thermally-treated commercial titanium dioxide (TiO₂) photocatalyst at room temperature (~30 °C) and ambient pressure. The effects of the operating conditions, including the catalyst loading level (1-6 g/L), UV light intensity (3.52-6.64 mW/cm²), initial pH...

This paper presents the results of preliminary assessment of water quality along Red Sea coast adjoining Jeddah, Saudi Arabia. Jeddah is a major city with a population of over 2.6 million and an area 1,200 km. To study the impacts, samples of the Red Sea were collected from 24 important locations near Jeddah and analyzed in the laboratory for various water quality parameters. These parameters i...

We study the interaction between product quality, prices and demand in a dynamic model of asymmetric information. Sellers choose between producing high quality goods which gives low profits today but increases probability of future survival in the market and low quality ones which gives higher returns today but lowers future survival. However, demand depends on expected quality. Multiple steady...

Demand models produce biased results when applied to data aggregated across stores with heterogeneous promotional activity. We show how to modify extant aggregate demand frameworks to avoid this problem. First a consumer-level model is developed, which is then integrated over the heterogeneous stores to arrive at aggregate demand. Our approach is highly practical since it requires only standard...

This paper investigates the question of how much information firms can acquire about the demand for their product when they learn from experience (i.e., from data about past sales and prices). The main issues are whether firms will eventually learn everything about the demand curve and how learning considerations affect the pricing decisions of firms. It is shown that even when the demand is de...

This paper provides evidence that a firm’s stock price movements affect its customer demand. I develop a model in which customers learn about a firm’s product quality partially from its stock price. This learning induces feedback from the price to customer demand. Furthermore, the firm manager adjusts product launch decisions in anticipation of these demand shifts. Consistent with the model’s i...

Multinational Companies, Backward Linkages and Labour Demand Elasticities This paper investigates the link between nationality of ownership and wage elasticities of labour demand at the level of the plant. In particular, we examine whether labour demand in multinationals becomes less elastic with respect to the wage if the plant has backward linkages with the local economy. Our empirical eviden...

Real-time monitoring of water quality for sewer system is required for efficient sewer network design because it provides information on the precise loading of pollutant to wastewater treatment facilities and the impact of loading on receiving water. In this study, synchronous fluorescence spectra and its first derivatives were investigated using a number of wastewater samples collected in sewe...

This paper examined the efficiency of multivariate linear regression (MLR) and artificial neural network (ANN) models in prediction of two major water quality parameters in a wastewater treatment plant. Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) as well as indirect indicators of organic matters are representative parameters for sewer water quality. Performance of the ANN m...

Some physico-chemical properties and the concentrations of the metals Fe, Mn, Ni, Cd, Cr, Co, Cu, Pb, and Zn in water and sediments were examined from September 2011 to January 2012 in Bodo Creek, where oil spills have been recurrent. Temperature, pH, total dissolved solid, conductivity, salinity, dissolved oxygen, biological oxygen demand (BOD), chemical oxygen demand (COD), total hardness, su...