POTENTIAL FUTURE CHALLENGES TO THE APPLICATION OF GAMMA IRRADIATION TO SEAFOOD IN TUNISIA

There is an increasing consumer demand for high quality, minimally processed, additive-free and microbiologically safe foods. The future application of irradiation to the seafood industry is developing. In order to investigate the feasibility of using gamma irradiation in the fish and seafood industry, questionnaires were distributed to the managers of 25 fish exporting companies. The cost of irradiation and the additional transport services were discussed and mostly accepted. This survey showed that essential conditions are to be found in Tunisia to introduce irradiation technology into the exporting seafood industry. However, the legal status of seafood irradiation varies in some importing countries (mainly European Union [EU]). Regulators within the EU have taken different approaches to allowing processors to use this technology. Such inconsistency is related to the objection of misinformed consumers. Consequently, commercial trade of irradiated seafood could be impeded.

PRACTICAL APPLICATIONS

This article provides evidence of the importance of industry managers' role in the food chain when testing the feasibility of a new process. Fish shelf-life extension using gamma irradiation is an emerging technology that presents many advantages to all food chain components and allows international trade requirements to be met. The seafood export industry in Tunisia shows the technological need for such a process. Furthermore, this study demonstrated that the economic cost of irradiation in Tunisia is acceptable and that it could enhance fish export capacity. However, the legal status of fish irradiation in the import countries, mainly the European Union, should be modernized in order to assure the feasibility of irradiated fish export from Tunisia.     

Variations in cycle time and certain physiological measures of workers performing a paced assembly task

Continuous monitoring of heart rate, respiration rate and galvanic skin resistance was done for 5 days on five subjects while they assembled drum brake cylinders. Cycle time and number of errors committed (unsuccessful hand movements) were also recorded. The subjects were required to perform the paced, repetitive task over an 8-hour period. Scheduled breaks, similar to local factories, were adhered to. A simple reaction test was given to measure attention. ANOVA on data showed that well rested subjects had higher physiological readings and committed more errors than subjects who had less sleep. An increase in CT and variability seems to be an indication of decrement in work performance and a rest period is needed. An increase in all four parameters is another indicator of poor performance (increase in errors). The simple repetitive task seems to be not motivating enough to keep the worker's attention and keep him aroused enough to work at his peak performance level     

The effect of visual angle and contrast ratio on inspection type tasks

A four alternative Choice Reaction Task, oil alternatives equally likely, was used to study the effect of size and contrast ratio of the visual stimulus on response time. A full factorial experiment was designed in which three levels of both the variables were tested. Sizes subtending visual angle of 1 min, 3 min, and 5 mill and the contrast ratios of 0-94, 0-75, and 0-34 were used. Seventeen subjects wore tested for this experiment and each subject responded 250 times under each experimental condition. The analysis has indicated that the contrast ratios tested did not significantly (a = 0'05) effect the response time.     

Information reduction and its effects upon performance times in a combined manual and decision task

To investigate the effect of information reduction on performance time while subjects performed combined manual and decision making tasks (type II), two sets of experiments were conducted. In the first set, five subjects performed a 3×2×2 completely randomized, factorial experiment in which three levels of information content in the stimuli, two levels of information in the responses and two levels of element reach were tested. The second set of experiments had three sub-sets. In each sub-set, information in the stimuli was different and was not considered as a variable and the 10 subjects reduced this information to given levels of information in the responses while performing reach of two different magnitudes. It has been found that information content in the stimuli (Ns_i), information content in the responses (NR_j) and reach (R_J) are significant variables that affect performance time. Performance time increases as the difference between Ns_i and NR_j decreases.     

Effect of task difficulty and angle in a positioning task involving symmetrical and asymmetrical motions

Task difficulty where simultaneous hand motions are involved may be defined for a given angle(s) of hand motion, as the magnitude of hand motion and the amount of control needed for completing the hand motions. The task difficulty has traditionally been measured using the following relationship: TD = log₂ 2D/C bits where D is the distance moved and C is the target diameter. Task difficulty and its effect on element position involving symmetrical and asymmetrical simultaneous motion does not seem to have been investigated in the past. In this paper results of experimental investigations are reported. The experiments included nine levels of task difficulty and three angles of hand motion for each symmetrical and asymmetrical simultaneous motion, Models for predicting performance times for ‘position’ involving symmetrical and asymmetrical simultaneous motions have been developed. A comparison of predicted time values using these models has been made with the values developed using some of the available predetermined motion time systems.     

Productivity study of apartment buildings maintenance systems

The fast-increasing world population is concentrating in urban areas. Today there are approximately 600 million housing units in the world. A fair portion of these units are apartments located in dense building areas in industrialized urban centres. The apartment building maintenance is an integrated subsystem of the urban system. There is a drastic increase in the productivity of maintenance when we institute centralized and rationalized apartment building maintenance system in place of traditional maintenance. The labour costs will decrease 40% and the technical maintenance costs 25%. With the acquisition value of organizing the system the total benefit of the centralized system is clearly profitable with all the possible interest rates and planning horizons.