D Amrani

Natural radioactivity in Algerian building materials

Samples of natural and manufactured building materials collected from Algiers have been analysed for 226Ra, 232Th and 40K using a high-resolution HPGe gamma-spectrometry system. The specific concentrations for 226Ra, 232Th and 40K, from the selected building materials, ranged from (12-65 Bq kg(-1)), (7-51 B qkg(-1)) and (36-675 Bq kg(-1)), respectively. The measured activity concentrations for these natural radionuclides were compared with the reported data of other countries and with the world average activity of soil. Radium-equivalent activities were calculated for the measured samples to assess the radiation hazards arising from using those materials in the construction of dwellings. All building materials showed Ra(eq) activities lower than the limit set in the OECD report (370 Bq kg(-1)), equivalent to external gamma-dose of 1.5 mSv yr(-1).

Computerized rotational system to study the moment of inertia of different objects

This paper describes a laboratory work that permits physics students to determine the moment of inertia for different objects. This experiment is computerized by using the Science Workshop data-acquisition system with the Datastudio software. The experimental results of the moment of inertia were in good agreement with the theoretical value.

Some investigations and use of LR-115 track detectors for radon measurements

Abstract Closed passive integrating radon dosimeters based on the use of cellulose nitrate (LR-115 type II) have been developed for assessment of long term radon exposure. This paper presents and comments the results of investigations, of registration efficiency, calibration factors, linearity tests and lower limit of detection for LR-115 detectors from different batches.

Investigating the relationship between the half-life decay of the height and the coefficient of restitution of bouncing balls using a microcomputer-based laboratory

This pedagogical activity is aimed at students using a computer-learning environment with advanced tools for data analysis. It investigates the relationship between the coefficient of restitution and the way the heights of different bouncing balls decrease in a number of bounces with time. The time between successive ball bounces, or time-of-flight, is used to determine the initial height and the coefficient of restitution due to the balls impact on a hard horizontal surface. The measurement techniques and the results obtained are pedagogically useful for undergraduate students during the manipulation and analysis of laboratory experiments dealing with the physics of bouncing balls.

Use of a current balance to calibrate an ammeter and to determine the magnetic permeability of free space

This paper describes a laboratory experiment using a current balance to check the calibration of an ammeter and to determine the magnetic permeability of free space. The current balance measures current by measuring the force between two parallel wires carrying that current. The results of each of the experiments are reported, and comparisons with theoretical predictions are included. The slope of ammeter reading versus measured current should be 1 and the intercept zero. The experimental values were 0.989 with an intercept of 0.25 and 1.008 with an intercept of 0.065 for current ranges from 2 to 15 A and 5 to 15 A, respectively. The calculated magnetic free space was 4.056π × 10−7 N A−2 and the difference between theoretical and experimental values was 1.4%.

Determination of Absolute Zero Using a Computer-Based Laboratory.

We present a simple computer-based laboratory experiment for evaluating absolute zero in degrees Celsius, which can be performed in college and undergraduate physical sciences laboratory courses. With a computer, absolute zero apparatus can help demonstrators or students to observe the relationship between temperature and pressure and use datalogger software to mathematically extrapolate to find absolute zero.