A non-linear numerical model for stratified Tsunami waves and its application

A non-linear numerical model is developed for the computation of water level and discharge for the propagation of a unidirectional two-layered tsunami wave. Four governing equations, two for each layer, are derived from Euler’s equations of motion and continuity, assuming a long wave approximation, negligible friction and no interfacial mixing. A numerical model is developed using a staggered Leap-Frog scheme. The developed non- linear model is compared with an existing validated linear model developed earlier by the author for different non-dimensional wave amplitudes. The significance of non-linear terms is discussed. It is found that for simulations of the interface wave amplitude, the effect of non-linear terms is not significant. However, for the simulation of the top surface, the effect of non-linear terms is significant for higher wave amplitudes, and insignificant for lower wave amplitudes. Developed non-linear numerical model is used for the case of a progressive internal wave in an inclined bay. It is found that the effect of an adverse bottom slipe towards the direction of wave propagation is to amplify the wave. This amplification depends on the steepness of slope as well as the ratio of densities of upper layer fluid to lower layer fluid (α). Amplification increases with slope. For higher values of α, amplification of the top and interface surface decreases, which is reasonable. It is also found that even for a 4 percent density difference between upper layer and lower layer, amplification of the top surface will be twenty times higher than amplification in the non-stratified case. The model can be applied confidently to simulate the basic features of different practical problems, similar to those investigated in this study

Numerical models of solar distillation device: present and previous

In this paper, a detailed comparison of a few numerical models (with and without considering humid air properties) for the estimation of water production from a solar water distillation device is investigated. An extensive laboratory production experiments were executed under fifteen sets of external conditions to find the properties of evaporation and condensation coefficients to incorporate with the present evaporation and condensation models (two unique and independent theoretical models), respectively. The calculation accuracy of the evaporation flux computed by two evaporation models (present and previous), Dunkle's and Ueda's model, and of the hourly condensation flux estimated by two condensation models (present and previous) was examined using the field experimental results. It was found that the previous evaporation and condensation models using empirical relationships extremely overestimated and underestimated the observed production flux, respectively. The evaporation flux calculated by the conventional models of Dunkle and Ueda notably underestimated and overestimated the observed values, respectively. Finally, it is revealed that the present models have the smallest deviation between the calculated and the observed values among these six models and can predict the daily production flux

Generalized equations for rainwater tank outcomes under different climate conditions: a case study for Adelaide

Most of the studies on rainwater tanks focused on sizing and/or optimum design. Some studies proposed different methods of estimating rainwater tank outcomes. Several studies used monthly rainfall data to estimate rainwater tank outcomes. However, quantification using daily rainfall data will be much more realistic than using monthly rainfall data. This paper presents development of generalised equations for domestic rainwater tank outcomes for an Australian city, Adelaide, using a daily water balance model, which incorporates measured daily rainfall data. To investigate the climate variabilities of rainwater tank outcomes, 15 representative years (five for each dry, average and wet condition) are selected from historical rainfall data. For the three climate conditions, rainwater tank outcomes such as water savings and town water augmentation amounts are presented in relation to tank volume, roof area and rainwater demand. Eventually, six equations, one for each climate condition and one for each outcome, are proposed

Uppföljning av matavfall i offentliga storkök i Sverige

One-third of all food production is wasted according to international estimations. United Nations have set an aim to reduce food waste by halving the amount by 2030 as food waste is responsible for creating much of the negative impacts on the environment. Food waste reduction is seen as one of the critical elements to achieving a sustainable food system under the EU food strategy. This study compiles food waste data from a large number of food serving places in Sweden. The information was collected from 822 kitchen units that recorded 609 tons of food waste from serving 7,683,650 meal portions served in Swedish public catering including Elderly care, Hospitals, Preschools, Primary schools, Secondary schools, and places that was a mixture of these categories. The data was recorded by the municipalities themselves and was then collected and compiled for the present study. The average waste per portion (in gram) throughout 2013 to 2020 were 122 g, 110 g, 65 g, 64 g, 96 g, and 51 g respectively in all sectors of catering units aggregated. In all sectors, the trend of food waste generation was declining to indicate that measures to reduce food waste are successful and contribute to a sustainable food syste

Thoughts of Chat GPT about Interaction Between Hypersonic Vehicles and Ice Crystal

This poster demonstrates the knowledge of ChatGPT regarding a contemporary research topic. The artificial intelligence was asked a set of questionnaires to narrow down a contemporary research idea. This poster also answers the question whether artificial intelligence can be used for developing a research idea or not. Lastly, this poster won the 3rd prize in the CHAT GPT poster contest category in CARS 2023 event.https://commons.und.edu/me-pp/1003/thumbnail.jp

Experimental Investigation Of Freezing Microdroplets For Understanding Chain Crystal Aggregates Observed In Atmospheric Clouds

Ice crystal aggregates are observed in upper stratospheric clouds. The crystal aggregates can form in different orientations, geometry, and shapes which are not well studied. These crystal aggregations are found in the clouds as crystal chains of various lengths and cause damage to hypersonic vehicles which include missiles, re-entry vehicles, and jet aircraft. The reasons behind such damage by atmospheric crystal chains to hypersonic bodies are unknown. That is why studying these ice crystals and their behavior in the hypersonic environment is necessary. Ice crystals form in the atmosphere in two different ways which are homogenous and heterogenous. Heterogenous freezing has been widely researched compared to homogenous freezing but cannot answer the ice crystal aggregation phenomena. Homogenous freezing is difficult to achieve in a lab environment due to its freezing nature. In this research, the adoption of two different methods to levitate water and microdroplets for initiating homogeneous freezing is discussed. These two different methods are the acoustic levitator and the dual balance electrodynamic trap (DBET). Acoustic levitator traps water droplets with the help of acoustic force and the DBET uses electrodynamic force to trap a micrometer-sized water droplet. With the incorporation of cooling systems along with these devices, the levitated water droplet can be frozen. In this research, the freezing procedure, size measurements, and images of different levitated ice shapes using an acoustic levitator are shown. This research also discusses the components, troubleshooting procedure, and a merging experiment of two charged 2.5wt% NaCl droplets using a DBET instrument in detail. A Cu coil tube has also been designed, incorporated, and insulated with the DBET to make ice crystals from levitated microdroplets which is a future work. The future work also includes ice crystals dropping from the acoustic levitator inside the shock tube to study and understand ice crystal behavior in the shock wave region. In relation to that a fall time calculation for spherical droplets inside the shock tube from several nodes of the acoustic levitator has also been presented here. For studying the ice crystal and shockwave interaction, precise time calculation between several components such as the time delay of myler bursting after entering the command, time for the shockwave to reach the viewing window, ice crystal falling time to the viewing window, high-speed camera recording etc. to be done inside the shock tube. This research also talks about the upcoming challenges and plans in brief to overcome those

Municipal solid waste recycling in Malaysia: present scenario and future prospects

This paper presents a current state-of-the art of municipal solid waste (MSW) management and recycling in Malaysia. It was revealed that mainly four sources were involved in the recycling program, e.g. recycle centers, recycle boxes, waste collectors and paper recyclers (by door to door collection system). On average, paper, aluminum, glass and plastic account for 63, 21, 15 and 1% of the recycled materials, respectively. The total waste generation was estimated to be 144 tons/day in Serdang and Seri Kembangan areas based on the number of collection vehicles, trips per day and vehicle capacity. The total recycled quantity was, however, about 2678 kg/day. Only 1.8% of total generated MSW was recycled, which is deemed to be very low compared to developed countries. Therefore, it is recommended to educate, motivate and encourage the citizens of Malaysia for reusing, recovering and recycling. It requires collaborative and consistent efforts, and technical know-how for a successful recycling program. Finally, some possible means of promoting the recycling program were recommended based on the current practice of developed countries. The first step would be the separation of recyclable items at sources or generation points. The local authorities and recycling organizations can play an important role in educating/motivating general mass through producing and disseminating appropriate guidelines

Investigating Liquid Droplets and Ice Crystals in the Atmosphere and Their Potential Damage to Hypersonic Vehicles

Ice crystal aggregates found in stratospheric clouds are detrimental to hypersonic flights. This poster demonstrates a method for generating ice crystals in the lab without physical touch using electrodynamic balance and shares a plan in upcoming years for investigating ice crystal interaction with shock waves.https://commons.und.edu/grad-posters/1007/thumbnail.jp

Experimental Investigation of Levitated Microdroplets for Understanding Chain Crystal Aggregates Observed in Atmospheric Clouds

This study talks about atmospheric ice crystal aggregation in the atmosphere and the process of generating ice crystal aggregate in a research lab using a dual-balance electrodynamic trap.https://commons.und.edu/grad-posters/1008/thumbnail.jp

Low-Temperature Laboratory Instrumentation for Investigating Ice Crystal Aggregate Formation in the Atmosphere

This study addresses the challenge of achieving controlled low temperatures to investigate and provide information on the precise conditions that promote homogenous (≤-38oC) and heterogenous (≥ -38oC) atmospheric ice crystal formation and aggregation, which disrupt aerospace industries and military activity. I present a preliminary design of a novel temperature control setup for generating levitated ice crystal aggregates within a Dual Balance Electrodynamic Trap (DBET). This preliminary design is called the replica low temperature electrodynamic balance (R-LTDBET). The design integrates chilled-coolant-conveying copper tubes encircling the hollow-square-shaped DBET’s external wall to precisely control its inner chamber temperature while incorporating real-time temperature sensing, control, and data analysis as the levitated microdroplets are frozen and aggregated within the R-LTDBET. Currently capable of cooling the R-LTDBET’s inner chamber to -9.0oC, this setup will be impl emented on the actual LT-DBET design for further testing and to generate experimental data that can provide valuable insight to aerospace engineers and atmospheric scientists designing hypersonic vehicles and developing precise cloud models which are poorly constrained in global atmospheric models. Future works aim to achieve lower temperatures, which enhances experimental insights into ice crystal structure and sticking potential.https://commons.und.edu/grad-posters/1009/thumbnail.jp