the valley of alamut is situated in the north – east of qazvin province. the region is an enclave in the form of a u shape valley in the central alborz chains and opening up to the fertile qazvin plains. the mountains of alamut were ideal for construction of castles. the natural heights contains a section of the defensive structure of the castles. in 1090 a.d, hassan sabbah , the leader of is...

The operating hourly cost of the machine is a suitable factor to analyze the cost fluctuation certain machinery in a changing environment and to find of economically feasible work concepts for the studied machine system. This paper, which is based on studies carried out in northern forests of IR-Iran, analyzed and compared costs of four skidding and excavation machines used in timber harvesting...

Mechanised tunnelling is characterised by a number of interacting components relevant for the excavation process (the soil including groundwater, the TBM, the linings, the support at the cutting face and the tail void) and by a staged process of excavation and lining erection. This imposes a considerable challenge for realistic modelling of the tunnelling process. The paper addresses recent adv...

Purpose. To investigate the prevalence and characteristics of focal choroidal excavation (FCE) concurrent with central serous chorioretinopathy (CSC) using multimodal imaging. Methods. This was a retrospective single-institution study. Clinical features and multimodal imaging findings were analyzed in eyes with CSC and FCEs, using imaging methods including optical coherence tomography (OCT), OC...

Automation of site preparation and resource utilization on the Moon with teams of autonomous robots holds considerable promise for establishing a lunar base. Such multirobot autonomous systems would require limited human support infrastructure, complement necessary manned operations and reduce overall mission risk. We present an Artificial Neural Tissue (ANT) architecture as a control system fo...

Collective construction of topologically complex structures is one of the triumphs of social behavior. For example, many ant species construct underground nests composed of networks of tunnels and chambers. Excavation by these 'superorganisms' depends on the biomechanics of substrate manipulation, the interaction of individuals, and media stability and cohesiveness. To discover principles of ro...

BACKGROUND To investigate possible differences in neuroretinal rim distribution, vascular pattern, and peripapillary region appearance between eyes with presumed large physiological optic disc cupping (pLPC) and eyes with minimal optic disc excavation. METHODS We prospectively enrolled consecutive subjects with pLPC and individuals with minimal excavation (optic disc excavation within normal ...

Termites construct complex mounds that are orders of magnitude larger than any individual and fulfil a variety of functional roles. Yet the processes through which these mounds are built, and by which the insects organize their efforts, remain poorly understood. The traditional understanding focuses on stigmergy, a form of indirect communication in which actions that change the environment prov...