The document analyzes two studies: 1) The first study evaluates the sedimentation process in rectangular channels used in cassava starch separation industries in Colombia. It examines how slurry concentration changes in the setting zone and particle size distribution. The study found slurry concentration varied between 0.1-6% and discrete particle settling predominated. 2) The second study analyzes sexual risk among Spanish adolescents based on their age of sexual debut. It found those with early debut (before 15) reported more partners and less condom use than other groups, suggesting early debut increases risk of STIs and poor condom habits. Both studies evaluate industrial processes and health risks.

1. ABSTRACT
JUAN CAMILO ORJUELA CADENA
11-2JM

2. Cassava starch separation
background :
The production of cassava starch in Colombia
comes mainly from the northem region of the
cauca department in small agricultural
industries know as “rallanderias”, in which the
setting of the slurry accurs in channels. Due to
the fact that the setting process determines the
capacity of the starch industry.

3. Aim or purpose of research
evaluate the process of sedimentation in
rectangular channels.
Method used
Two main components were evaluated:
determination of the change in the
concentration of the slurry entering the setting
zone and determination of the particle size
distribution in the setting zone.

4. Results
In relation to the affluent of the clannels, it was
found that concentration of the slurry during
strainer operation was between 0.1 to 6% most
of the time; the setting of discrete particles, for
wich the stokes law may be applied
predominate.

5. Conclusion
During the setting process, the flow varied
between 0,82 to 1,44 l/s with a predominance
of laminar flow and a hydraulic retention time
greater than 150 minutes.

6. Sexual risk in adolescents
depending on the age of sexual
debut
Background
During adolescence and young adulthood are
maintained the first intimate relations ships
and the period starts exposure to sexually
transmited infections (stis). The age of first
intercourse has decreased considerably in
recent decades, standing before 18 years many
countries (wellings et al, 2006).

7. Aim or porpuse of research
Analyze sexual risk by age of sexual debut.
Methods
Sexual practices and methods of protection are
analyzed depending on the age of sexual debut
among Spanish adolescents who are sexually
experienced (N = 351). The mean age was 15.9
years (SD = .75, range: 14-18). Three groups
were formed according to the age of sexual
debut reported: early sexual debut (earlier than
15 years), average (15 years) and late (later than
15 years).

8. resulds
The early sexual debut group reported further
mutual masturbation, vaginal intercourse and oral
sex with a higher number of sexual partners than
the rest. Condom use at first intercourse,
percentage of use and consistent condom use was
significantly lower in the early sexual debut group
compared to the others. Sexual debut before 15
years old was associated with increased risk of
sexual infections, deficit in condom use and
increased sexual exposure.
conclusion
The findings of this study suggest that the age of
sexual debut has implications for the sexual health
in young people.

9. ANEXOS