The influence of praseodymium (Pr) content on the solidification characteristics, microstructure, and mechanical properties of

ZRE1 magnesium (Mg) cast alloy was investigated. The obtained solidification parameters showed that Pr strongly affected the solidification 

time, leading to refinement of the microstructure of the alloys. When the freezing time was reduced to approximately 52 s, the grain size de-

creased by 12%. Mg12Zn (Ce,Pr) was formed as a new phase upon the addition of Pr and was detected via X-ray diffraction analysis. The ad-

dition of Pr led to a substantial improvement in mechanical properties, which was attributed to the formation of intermetallic compounds; the 

ultimate tensile strength and yield strength increased by approximately 10% and 13%, respectively. Pr addition also refined the microstruc-

ture, and the hardness was recovered. The results herein demonstrate that the mechanical properties of Mg alloys are strongly influenced by 

their microstructure characteristics, including the grain size, volume fraction, and distribution of intermetallic phase

Abstract

Insect host preference by the larval pupal endoparasitoid Opius. pallipes was studied in Ojilate region in western Libya using broad bean (Vecia faba) as a host plant and the two leafmininig species, the American serpentine leaf miner Liriomyza trifolii (Burgess) and the tomato leaf miner Liriomyza bryonia (Kaltenbach). Three peaks of abundance were recorded by O. pallipes on both insect hosts L. bryonia and L. trifolii. On brad bean a peak was exhibited with (81 individuals/ 100 infested leaflets) with L. trifolii whereas a peak of (31 individuals/ 100 infested leaflets) was exhibited with L. bryonia. The lowest count was observed with (33 individuals/ 100 infested leaflets) on L. trifolii and with (27 individuals/ 100 infested leaflets) on L. bryonia. Under laboratory conditions, insect host preference of the parasitoid O. pallipes was tested. The Results indicated that number of eggs and parasitized larvae per parasitoid female were significantly higher on L. trifolii than L. bryonia in the choice test with (9.2±3.9 eggs/female and 7.0±2.9 host larvae/female, on L. trifolii than L. bryonia respectively). On the other hand number of parasitized larvae per female was significantly higher in no choice test with (9.2±2.3 parasitized larva/female and 7.1±3.0 parasitized larva/female, on L. trifolii than L. bryonia respectively)

AAPG "Siliciclastic Reservoirs of the Middle East" GTW took place from 15-16 May 2017 at the Grand Hyatt Amman Hotel in Jordan.

The workshop was dedicated to knowledge sharing, exchanging ideas and workflows pertaining to exploration and development of siliciclastic reservoirs in the Middle East region. 44 industry professionals from 9 countries and 16 companies attended the workshop. The 15 presentations which formed the technical program covered the following topics:

• Integrated Stratigraphic Techniques and Studies: A Better Way of Correlation
• Understanding the Depositional Environments and Processes of Clastic Reservoirs
• Structure, Geomechanics and Fluid Flow Properties of Siliciclastic Reservoirs
• Diagenetic Controls on Reservoir Quality: Assessment and Prediction

Core provided by National Petroleum Company, Jordan and Saudi Aramco was on display throughout the workshop. The core was carefully selected to compliment the technical program and participants had time each day to view and discuss the core samples.

Highlights of the workshop included two inaugural keynote speeches delivered by:

• Sa'id Al Hajri, Saudi Aramco, AAPG Middle East Past President
• Abdulkaker Abed, Professor of Geology, University of Jordan

All of the attendees also benefitted from informative breakout discussion sessions, held at the end of each day.

The workshop was followed by an optional two-day field trip to Wadi Rum (17-18 May 2017), led by Ahmed Masri, Ministry of Energy and Mineral Resources, Jordan.

We would like to take this opportunity to sincerely thank Saudi Aramco as the Platinum Sponsor of this workshop.

in Higher education sector, assessment criteria are important in measuring students‟ learning and support teaching. The assessment of students EFL writing could help in identifying students‟ learning needs, progress and also teaching. This research examines university tutors and students understanding of assessment criteria used in EFL writing skills. The analysis shows important finding that most of the tutors did not inform students about assessment criteria or discuss them which affected the students‟ ability to gain higher grades and produce better work. This might be due to lack of knowledge about the importance of providing and involving students in the criteria. The finding prompts a re-thinking about the use of assessment criteria and could make significant contribution to improve and provide great insights into the education especially in the Libyan context and in an EFL context.