urbanization agglomeration that is named jacobs externalities, refers to the role of economic diversification in urban. localization agglomeration, marshal-arrow-romer (mar) externalities, is related to the concentration of firms activated in a special industry within a specified place. the purpose of this research is to explore the impact of different types of agglomeration economies on employ...

The one-piece flow manufacturing line of single and customized products is usually organized as a U-shaped assembly layout. In this study, the characteristics of a single U-line are described and modeled. The worker allocation problem is hierarchically concerned with the task assignment into a U-line and allocate task to workers in sequence. Several products are assembled in 7-task to 297-task ...

Fabrication and characterization of U-shaped fiber optic pH probes utilizing evanescent field absorption spectroscopy and dye doped solgel immobilization technology are presented. The U-shaped probe is used to increase the evanescent field in the film and hence its interaction with the dyes present in the film. The influences of bending radius of the probe and the numerical aperture of the fibe...

Recent approaches used to characterize the elastic or viscoelastic properties of materials with nanoscale resolution have focused on the contact resonances of atomic force microscope (CR-AFM) probes. The experiments for these CR-AFM methods involve measurement of several contact resonances from which the resonant frequency and peak width are found. The contact resonance values are then compared...

In manual order picking systems, order pickers walk or ride through a warehouse in order to collect items requested by customers. The performance of such a system is significantly dependent on its layout which determines the lengths of the order pickers’ tours and the corresponding picking times. Whereas for classic warehouse layouts all picking aisles are arranged in parallel to each other, in...

Microstrip antennas are widely used in many applications due to their low profile, low cost and ease of fabrication. In some applications it is desired to have a dual band or multiband characteristics. These characteristics can be obtained by coupling multiple radiating elements or by using tuning devices such as varactor diodes [1, 2]. However, these methods make antenna more complicated. A si...

This paper details a simple and general account, and model, of the U-shaped curve phenomena apparent in many developmental psychology experiments. The model replicates both the general form of the U-shape performance in ongoing development and accounts for additional observations in the psychology literature such as the effect of noise in Switch task experiments. This leads to predictions both ...

The design of a simple small-size antenna for worldwide interoperability for microwave access (WiMAX) application is presented in this paper. The antenna covers the 3-5 GHz WiMAX band. The proposed printedtype antenna is based on a 1.6 mm-thick FR4 epoxy substrate with dimensions W=25 mm and L=40.5 mm. It has a rectangular split-ring slot enclosed inside a rectangular patch. The inclusion of th...

In a recent paper entitled "Circulating 25-Hydroxyvitamin D and the Risk of Pancreatic Cancer," Stolzenberg-Solomon et al. reported that the odds ratio for diagnosis of pancreatic cancer shows a "statistically significant" precipitous jump of more than a factor of 2 at the highest presented concentrations of >100 nmol/l. This was one of six related studies of the relation of 25-hydroxyvitamin D...

The subject of light transmission through optically thin metal films perforated with arrays of subwavelength nanoholes has recently attracted significant attention. In this work, we present experimental and calculated results on optical transmission/reflection of the U-shaped nanoapertures for enhanced optical transmission and resolution. We propose different structure designs in order to prove...