This report is based on the assessment of four heavy metals: lead, chromium, nickel, and copper, in thirty-two roadside soil samples, one of which was a virgin soil, in Zawia City, Libya. During spring 2019, soil samples were collected from five sites along Jamal Street starting from the old university building to Al-Shuhadaa Square. The atomic absorption spectrometer Perkin Elmer AAnalyst 400 was used in this study using absorption mode, except for the use of Cu emission mode due to the unavailability of the Cu lamp. Results showed that the highest concentrations of the investigated elements were: 36 mg/kg for Pb, 15.6 mg/kg for Cr, 8.3 mg/kg for Ni, and 50 mg/kg for Cu. These values are in agreement with the allowable values of heavy metal concentration of soils in some European countries (i.e. Austria, Germany, and France). However, the concentration values for Pb, Cr, Ni, and Cu were 5.2, 2.9, 2.3, and 7.8 fold higher, respectively, than that of the virgin soil sample collected about 10 km away from the city centre. The sample preparation method used in this work was demonstrated to be suitable, showing acceptable recovery values (R%) of 94.6%, 81.9%, 87.6%, and 90.7% for Pb, Cr, Ni, and Cu, respectively.
Ragiab A M Issa(4-2020)

تتمثل مشكلة هذا البحث في الإجابة على التساؤلات التالية:- 1. كيف تنمو البنيات المعرفية ويكتسب الفرد المعرفة من منظور بياجيه؟ 2. ماهي مراحل النمو العقلي المعرفي وفق نظرية بياجيه؟ يهدف هذا البحث إلى الآتي: التعرف على آلية اكتساب الفرد للمعارف والخبرات وتكوين البنيات المعرفية الجديدة، والكشف عن مراحل النمو العقلي المعرفي وفق تقسيم العالم بياجيه. arabic 90 English 66
مسعودة مفتاح أحمد عبدالرحمن الحسيني(1-2018)

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أ.أحمد علي ناجي(1-2020)