Thermal efficiency improvement of a solar desalination process by parabolic trough collector

The nexus water/energy security is one of the main global challenges for the future generation. Solar distillation (thermal process) represents a sustainable solution to water shortages and energy crisis in the world especially in Middle East and North Africa region. The technique is based on evaporation-condensation process via heat delivery through a Cylindrical Parabolic Collector to a Thermal Energy Storage, in the form of sand integrated into the solar still, to maximize water production efficiencies. It is a technically feasible and operational method. Results suggest that the additional solar collector flux has a direct impact on the increase in average sand and seawater temperature particularly over the period between 12:00pm and 04:00pm. Seawater temperature increases by >26.6%. The energy stored quantity delivered for the distiller basin grows proportionality with the sand temperature, which is depending directly for the solar collector absorber temperature. The difference between the both temperatures defines a decreasing rate of −19%. The daily water production by the hybrid solar distiller is 6.5 l/day, it represents an increase of +91% compared to the traditional concrete solar still production (3.4 l/day), for the same geometry and meteorological conditions.

Influence of short-term temperature drops on sex-determination in sea turtles

All sea turtles exhibit temperature-dependent sex-determination, where warmer temperatures produce mostly females and cooler temperatures produce mostly males. As global temperatures continue to rise, sea turtle sex-ratios have become increasingly female-biased, threatening the long-term viability of many populations. Nest temperatures are dependent on sand temperature, and heavy rainfall events reduce sand temperatures for a brief period. However, it is unknown whether these short-term temperature drops are large and long enough to produce male hatchlings. To discover if short-term temperature drops within the sex-determining period can lead to male hatchling production, we exposed green and loggerhead turtle eggs to short-term temperature drops conducted in constant temperature rooms. We dropped incubation temperature at four different times during the sex-determining period for a duration of either 3 or 7 days to mimic short-term drops in temperature caused by heavy rainfall in nature. Some male hatchlings were produced when exposed to temperature drops for as little as 3 days, but the majority of male production occurred when eggs were exposed to 7 days of lowered temperature. More male hatchlings were produced when the temperature drop occurred during the middle of the sex-determining period in green turtles, and the beginning and end of the sex-determining period in loggerhead turtles. Inter-clutch variation was evident in the proportion of male hatchlings produced, indicating that maternal and or genetic factors influence male hatchling production. Our findings have management implications for the long-term preservation of sea turtles on beaches that exhibit strongly female-biased hatchling sex-ratios.

Effectiveness of Sea Turtle Conservation Management at the Turtle Conservation and Education Center of Serangan, Denpasar Bali

Turtles are one of the reptile animals that can migrate long distances along the Indian Ocean, Pacific Ocean and Southeast Asia. The purpose of turtle migration is to mate, find spawning locations and to find food. Sea turtles have an important role in maintaining the balance of the marine ecosystem. However, the high utilization of sea turtles by humans causes the turtle population to decline. One of the conservation sites that help the government program is in Serangan, Denpasar Bali, namely the TCEC (Turtle Conservation and Education Center), where there are several types of turtles such as the lekang turtle, hawksbill and green turtle. Data collection techniques in this study used observation methods including beach monitoring, relocation of turtle eggs to semi-natural hatchery hatching, hatchling and turtle nesting as well as measurement of turtle length and width carapase curve (CCL/CCW), sand temperature, nest depth, nest diameter, nest distance and nest calculation of the number of eggs to see the success of hatching. The results are turtle conservation activities, ranging from turtle maintenance, hatching of turtle eggs, relocation of eggs, and maintenance of hatchlings to release turtles. The effectiveness given by TCEC to manage and preserve the existence of sea turtles in Indonesia, especially in the Bali region is to provide awareness to the community by not consuming eggs and turtle meat.

Sand temperature and moisture monitoring system for turtle nests using Arduino Uno

This study aims to develop a turtle nests real-time monitoring system using the Arduino Uno to measure the temperature and moisture of sand used conveniently for certain applications. Sand temperature measurement uses a DS18B20 waterproof sensor, sand moisture uses SKU:SEN0193, and air temperature and humidity using DHT22. The micro SD card module is used to store data from sensor calculations in real-time and continuously. The measuring instrument was designed to be portable and easy to use. The material used is polypropylene that has dimensions of 11x6x18 cm3. Using the regression linear analysis, there was no significant difference in temperature measurements using the DS18B20 sensor and analog thermometer and sand humidity using an SKU:SEN0193 sensor and analog humidity measuring instrument.

Suhu inkubasi, pasir pantai peneluran dan sukses penetasan telur penyu pada sarang semi alami di Pantai Warebar - Yenbekaki Distrik Waigeo Timur, Kabupaten Raja Ampat

The research took place between May and October 2019, and divided into two stages. The first stage was field research to collect data by identifying turtles, calculating hatching successes, measuring the temperature of the nesting beach and nest temperature of each species of turtle in semi-natural nests at Warebar Beach, Yenbekaki village, East Waigeo Sub District, Raja Ampat. The second stage after the field was conducting an analysis of hatching rate in hatchery, sand temperature and nest temperature for each species of turtle. The species of turtles nesting at Warebar Beach are olive-ridley (Lepidochelys olivacea) and hawksbill (Eretmochelys imbricata) turtles. Based on the measurement results at semi-natural nests, it was obtained that the hatching rate of olive ridley sea turtle was 71.6%±28.3 (X±SD) and hawksbill sea turtle was 59.8%±41.3, the overall mean temperature of nesting beach was 28oC, the mean incubation temperature for both sea turtle species was 31oC.

Analysis of Seepage in a Laboratory Scaled Model Using Passive Optical Fiber Distributed Temperature Sensor

Seepage is the key factor in the safety of dikes and earth-fill dams. It is crucial to identify and localize the seepage excesses at the early stages before it initiates the internal erosion process in the structure. A proper seepage monitoring system should ensure a continuous and wide area seepage measurement. Here, continuous monitoring of seepage at the laboratory-scale is achieved by a passive optical fiber Distributed Temperature Sensing (DTS) system. An experimental model was designed which consists of initially unsaturated sand model, water supply, seepage outflow, optical fiber DTS system, and water and air temperature measurement. Initially, the sand temperature was higher than the temperature of the seepage water. An optical fiber DTS system was employed with a high-temperature resolution, short sampling intervals and short time intervals for temperature monitoring in the sand model. In the system, the small variation in the temperature due to groundwater flow was detected. The numerical analysis was conducted for both the seepage process and the heat transfer progression in the sand model. The results of the heat flow simulation were evaluated and compared with the measured temperature by the optical fiber DTS. Obvious temperature reduction was obtained due to seepage propagation in the sand. The rate of temperature reduction was observed to be dependent on the seepage flow velocity.

Ricochet of Spheres on Sand of Various Temperature

The debris generated by the explosion of a building or ammunition is flown far away through the ricochet phenomenon. The debris contains a very large amount of energy, and a risk factor surrounding it may be applied. The safety distance from debris is set from experiments or FEM analysis. The ricochet of debris is affected not only by the initial conditions of the debris, but also by the conditions of the medium. In this paper, the effect of sand temperature on the ricochet of sphere projectiles was investigated through experiments and FEM, by measuring the shear stress and internal friction angle when the sand temperature increases. As the temperature of the sand increases, the shear stress and the internal friction angle decrease, and the penetration depth of the projectile increases. As the depth of penetration becomes longer, the kinetic energy is lost more by the friction force with the sand and, the sphere projectile speed decreases more. This is mainly caused by the energy loss of the projectile, so the kinetic energy of the ricocheted projectile is reduced. Therefore, when setting the optimized inhabited building distance (IBD), the conditions of the medium should be taken into account.