the aim of this paper is eliminating cr(vi) by natural hap. hap is a inexpensive material which is used from bovine critical bone ash in order to remove heavy metal ions like cr(vi). some experiments in different ph are performed (ph=2,3,7). maximum adsorption was appeared at ph=2, dosage=0.3 gr, c0=10 mg/l. cr(vi) removal depends on ph value and initial amount of cr(vi) result of experiments w...

abstract: country’s fiber optic network, as one of the most important communication infrastructures, is of high importance; therefore, ensuring security of the network and its data is essential. no remarkable research has been done on assessing security of the country’s fiber optic network. besides, according to an official statistics released by ertebatat zirsakht company, unwanted disconnec...

this study aimed to investigate the effects of listening strategy training on iranian efl learners listening comprehension and use of such strategies. this work, employing an experimental methodology, was conducted among 60 adult efl learners from a language institute in isfahan, iran, as participants. the participants, who were selected based on the results of a placement test, were assigned t...

any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...

the author intend to by studying the historical causes of the appearance of the novation in the west and explanation of its legal nature from past to present of french law, proves on the one hand that the novation does not extracted from the french civil code and in the shiite jurisprudence with quite similar terms even before the enactment of iranian civil code, was considered by the shiite su...

in this research the focus of the researcher is on the influence of american myths that have long been held and offered by the american culture and ideologies. sam shepard is conceived to be one of the greatest playwrights of the contemporary american theater. in his works he depicts broken characters who are struggling to keep up with the national expectations but are ceaselessly borne back to...

abstract the aim of the present study is to explore the impact of the cognitive reading strategy instruction on learners reading self-efficacy and their reading achievement. in order to fulfill this purpose, from 120 participants, 90 intermediate efl learners as an experimental group were chosen from three different educational settings namely, yazd university, yazd science and art un...

learning a second or foreign language requires the manipulation of four main skills, namely, listening, reading, speaking, and writing which lead to effective communication. it is obvious that vocabulary is an indispensible part of any communication, so without a vocabulary, no meaningful communication can take place and meaningful communication relies heavily on vocabulary. one fundamental fac...

like any other learning activity, translation is a problem solving activity which involves executing parallel cognitive processes. the ability to think about these higher processes, plan, organize, monitor and evaluate the most influential executive cognitive processes is what flavell (1975) called “metacognition” which encompasses raising awareness of mental processes as well as using effectiv...