Water-Trap Series and City Pond to Control The Destructive Power of Runoff Water from Mbay Hills

Weworuwet Hill, which is part of the Mbay hillside in Flores – NTT has sparse vegetation, only a stretch of grass that covers it, and is dry in the dry season like a barren teletabic hillside. This has the potential for surface water runoff, which has high destructive power, especially in the lowlands of Mbay City. To overcome this problem, a study to control the destructive force of water runoff was carried out by applying a water-trap series system, so that the potential for the destructive power of water can be reduced. Tertiary, secondary and primary runoff analysis studies are carried out to determine the location of the required watertraps. This study was conducted using a geographic information system-based program. Furthermore, the hydrological analysis of the area is carried out to determine which flood discharge can be controlled, and the volume of water that can be used for greening hills so that it can reduce the potential for damage to water runoff. The remaining water discharge in the downstream will be accommodated in the city pond, which functions as water conservation infrastructure. Finally, by applying a series of water traps on the tertiary, secondary and primary runoff from the Mbay hilly area, the destructive power of the runoff can be controlled, so that it does not impact and burden the residential plains of the town of Mbay.

Building Drainage System Design for Tall Buildings: Current Limitations and Public Health Implications

National design guides provide essential guidance for the design of building drainage systems, which primarily ensure the basic objectives of preventing odor ingress and cross-transmission of disease through water-trap seal retention. Current building drainage system design guides only extend to buildings of 30 floors, while modern tall buildings frequently extend to over 100 floors, exceeding the predictive capability of current design guides in terms of operating system conditions. However, the same design guides are being used for tall buildings as would be used for low-rise buildings. A complicating factor is the historic roots of current design guides and standards (including the interpretation of the governing fluid mechanics principles and margins of safety), causing many design differences to exist for the same conditions internationally, such as minimum trap seal retention requirements, stack-to-vent cross-vent spacing, and even stack diameter. The design guides also differ in the size and scale of the systems they cover, and most make no allowance for the specific building drainage system requirements of tall buildings. This paper assesses the limitations of applying current building drainage system design guides when applied to the case of tall buildings. Primarily, the assessments used in this research are based on codes from Europe, the USA and Australia/New Zealand as representative of the most common approaches and from which many other codes and standards are derived. The numerical simulation model, AIRNET, was used as the analysis tool. Our findings confirm that current design guides, which have been out of date for a number of decades, are now in urgent need of updating as code-compliant systems have been shown to be susceptible to water-trap seal depletion, a risk to cross-transmission of disease, which is a major public health concern, particularly in view of the current COVID-19 pandemic.

Design and placement of synthetic sex pheromone traps for cacao mirids in Ghana

Cacao mirids (Sahlbergella singularis,Distantiella theobromaandBryocoropsis laticollis) were captured in pheromone traps releasing a 2:1 blend of the sex pheromone components of the two first named species in a series of five experiments on cacao (Theobroma cacao) plantations in Ghana. A total of 835 cacao mirids were caught, all male, 95% of which wereS. singularis, 3%D. theobromaand 2%B. laticollis.Two sticky trap and two water trap designs made from locally available materials were as effective for capturingS. singularisand total mirids as the best sticky trap from previously reported studies. Coating the outer surface of a large water trap with sticker increased the catch 4.4×, and 2.7× for a cylindrical sticky trap. Sticker on the outside of the water trap also increased the inside catch ofS. singularisby 76% and total mirids by 71%. The numbers ofS. singularisandD. theobromatrapped increased with increasing trap elevation and were highest around canopy level. Those traps caught an average 12× more mirids than traps at 1.8 m, the height recommended currently. Therefore, large water traps coated with sticker and aligned with the cacao canopy should raise the current capture rates of pheromone traps for cacao mirids about 50×, which may be sufficient for effective pest management by mass trapping without synthetic insecticides.

Modelling water trap seal boundary conditions in building drainage systems: Computational fluid dynamics analysis of unsteady friction to improve accuracy

The safe removal of disease-carrying human waste is the objective of all sanitation systems and the limiting of air pressure transients within the system remains a significant part of current codes and regulations. The water trap seal offers fundamental protection and is the system’s sole barrier between the public sewer network and habitable space inside a building. Modelling water trap seal responses to air pressure fluctuations offers an opportunity to analyse whole system performance, but the quality of the data depends on the accuracy of the modelling technique and that of the defining inputs. AIRNET, a 1D Method of Characteristics based model, enables rapid whole system testing; however, the present boundary condition for the water trap seal within the model is based solely on steady state conditions, ignoring system dynamics. Computational fluid dynamics offers an opportunity to numerically evaluate the flow patterns within the trap seal in response to applied air pressure transients. This research confirms the importance of the rate of rise, and hence frequency of air pressure transients incident on water trap seals and relates this to potential vulnerabilities of different device geometries, particularly the ratio between inner and outer wall length. The research led to the development of a dynamic velocity decrement model encapsulating unsteady friction and separation losses linked to device geometry for the first time. The development of a frequency-dependent internal energy term Δ v, suitable for inclusion in AIRNET provides the capability to predict more realistic water trap response to air pressure transients over a range of air pressure transient frequencies likely to cause problems: 1 Hz to 8 Hz. Practical application: Whole system modelling can greatly improve the ability of design engineers to fully simulate the operation of a building drainage system in a realistic way. The work described in this paper improves the accuracy of whole system models by evaluating water dynamic responses to air pressure transients using a range of techniques including computational fluid dynamics and more traditional 1D finite difference method of characteristics models. The work also paves the way for more robust evaluation of building drainage products through in-depth investigation of the fluid mechanics associated with their operation.

PENELITIAN AIR TANAH DI WADUK PUNTUK SURUH KECAMATAN PENGADEGAN KABUPATEN PURBALINGGA – JAWA TENGAH

Based on groundwater indication map, the area of Pengadegan district, PurbalinggaRegency, has low groundwater resources potential for both deep and shallowgroundwater.Investigation using resistivity showed that the potential water layers were found inthe eastern part of the Dam at B and C layers. The groundwater is shallow and thethickness of the aquifer is about 20 meter and extent horizontally up to 30 meter.Layer A and B in the western part of the Dam are possibly act as a water trap asthey lies above a compact layer E.To know the potential groundwater area it is suggested that further research andsurvey be done in the eastern part of the Dam.