Search results for: deformation demand

Authors: Soojin Kim, Jiwon Yang, Sungzoon Cho

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As a seasonal product is only in demand for a short time, inventory management is critical to profits. Both markdowns and stockouts decrease the return on perishable products; therefore, researchers have been interested in the distribution of seasonal products with the aim of maximizing profits. In this study, we propose a data-driven seasonal product sales pattern analysis method for individual retail outlets based on observed sales data clustering; the proposed method helps in determining distribution strategies.

Keywords: clustering, distribution, sales pattern, seasonal product

Procedia PDF Downloads 595

Authors: Haile Araya Nigusse, Hiram M. Ndiritu, Robert Kiplimo

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Energy consumption is an indispensable component for the continued development of the human population. The global energy demand increases with development and population rise. The increase in energy demand, high cost of fossil fuels and the link between energy utilization and environmental impacts have resulted in the need for a sustainable approach to the utilization of the low grade energy resources. The Organic Rankine Cycle (ORC) power plant is an advantageous technology that can be applied in generation of power from low temperature brine of geothermal reservoirs. The power plant utilizes a low boiling organic working fluid such as a refrigerant or a hydrocarbon. Researches indicated that the performance of ORC power plant is highly dependent upon factors such as proper organic working fluid selection, types of heat exchangers (condenser and evaporator) and turbine used. Despite a high pressure drop, shell-tube heat exchangers have satisfactory performance for ORC power plants. This study involved the design, fabrication and performance assessment of the components of a model Organic Rankine Cycle power plant to utilize the low grade geothermal brine. Two shell and tube heat exchangers (evaporator and condenser) and a single stage impulse turbine have been designed, fabricated and the performance assessment of each component has been conducted. Pentane was used as a working fluid and hot water simulating the geothermal brine. The results of the experiment indicated that the increase in mass flow rate of hot water by 0.08 kg/s caused a rise in overall heat transfer coefficient of the evaporator by 17.33% and the heat transferred was increased by 6.74%. In the condenser, the increase of cooling water flow rate from 0.15 kg/s to 0.35 kg/s increased the overall heat transfer coefficient by 1.21% and heat transferred was increased by 4.26%. The shaft speed varied from 1585 to 4590 rpm as inlet pressure was varied from 0.5 to 5.0 bar and power generated was varying from 4.34 to 14.46W. The results of the experiments indicated that the performance of each component of the model Organic Rankine Cycle power plant operating at low temperature heat resources was satisfactory.

Keywords: brine, heat exchanger, ORC, turbine

Procedia PDF Downloads 649

Authors: R. Horchani

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Optical pumping technique with laser fields combined with photo-association of ultra-cold atoms leads to control on demand the vibrational and/or the rotational population of molecules. Here, we review the basic concepts and main steps should be followed, including the excitation schemes and detection techniques we use to achieve the ro-vibrational cooling of Cs2 molecules. We also discuss the extension of this technique to other molecules. In addition, we present a theoretical model used to support the experiment. These simulations can be widely used for the preparation of various experiments since they allow the optimization of several important experimental parameters.

Keywords: cold molecule, photo-association, optical pumping, vibrational and rotational cooling

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Authors: David W. Hill, Linda W. Glass, Jakob L. Vingren

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Maximal accumulated oxygen deficit (MAOD), the gold standard measure of anaerobic capacity, is the difference between the oxygen cost of exhaustive severe intensity exercise and the accumulated oxygen consumption (O2; mL·kg–1). In theory, MAOD can be estimated as the sum of independent estimates of the phosphocreatine and glycolysis contributions, which we refer to as PCr+glycolysis. Purpose: The purpose was to test the hypothesis that PCr+glycolysis provides a valid measure of anaerobic capacity in cycling and running. Methods: The participants were 27 women (mean ± SD, age 22 ±1 y, height 165 ± 7 cm, weight 63.4 ± 9.7 kg) and 25 men (age 22 ± 1 y, height 179 ± 6 cm, weight 80.8 ± 14.8 kg). They performed two exhaustive cycling and running tests, at speeds and work rates that were tolerable for ~5 min. The rate of oxygen consumption (VO2; mL·kg–1·min–1) was measured in warmups, in the tests, and during 7 min of recovery. Fingerprick blood samples obtained after exercise were analysed to determine peak blood lactate concentration (PeakLac). The VO2 response in exercise was fitted to a model, with a fast ‘primary’ phase followed by a delayed ‘slow’ component, from which was calculated the accumulated O2 and the excess O2 attributable to the slow component. The VO2 response in recovery was fitted to a model with a fast phase and slow component, sharing a common time delay. Oxygen demand (in mL·kg–1·min–1) was determined by extrapolation from steady-state VO2 in warmups; the total oxygen cost (in mL·kg–1) was determined by multiplying this demand by time to exhaustion and adding the excess O2; then, MAOD was calculated as total oxygen cost minus accumulated O2. The phosphocreatine contribution (area under the fast phase of the post-exercise VO2) and the glycolytic contribution (converted from PeakLac) were summed to give PCr+glycolysis. There was not an interaction effect involving sex, so values for anaerobic capacity were examined using a two-way ANOVA, with repeated measures across method (PCr+glycolysis vs MAOD) and mode (cycling vs running). Results: There was a significant effect only for exercise mode. There was no difference between MAOD and PCr+glycolysis: values were 59 ± 6 mL·kg–1 and 61 ± 8 mL·kg–1 in cycling and 78 ± 7 mL·kg–1 and 75 ± 8 mL·kg–1 in running. Discussion: PCr+glycolysis is a valid measure of anaerobic capacity in cycling and running, and it is as valid for women as for men.

Keywords: alactic, anaerobic, cycling, ergometer, glycolysis, lactic, lactate, oxygen deficit, phosphocreatine, running, treadmill

Procedia PDF Downloads 136

Authors: Saeed Kamarian

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In this paper, free vibrations of Functionally Graded Sandwich (FGS) beams reinforced by randomly oriented Single-Walled Carbon Nanotubes (SWCNTs) are investigated. The Eshelby–Mori–Tanaka approach based on an equivalent fiber is used to investigate the material properties of the structure. The natural frequencies of the FGS nanocomposite beam are analyzed based on various Higher-order Shear Deformation Beam Theories (HSDBTs) and using an analytical method. The verification study represents the simplicity and accuracy of the method for free vibration analysis of nanocomposite beams. The effects of carbon nanotube volume fraction profiles in the face layers, length to span ratio and thicknesses of face layers on the natural frequency of structure are studied for the different HSDBTs. Results show that by utilizing the FGS type of structures, free vibration characteristics of structures can be improved. A comparison is also provided to show the difference between natural frequency responses of the FGS nanocomposite beam reinforced by aligned and randomly oriented SWCNT.

Keywords: sandwich beam, nanocomposite beam, functionally graded materials, higher-order beam theories, Mori-Tanaka approach

Procedia PDF Downloads 462

Authors: Ju-Young Choi, Ki-Il Song, Kyoung-Yul Kim

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During Tunnel Boring Machine (TBM) tunnel excavation, backfill grout should be injected after the installation of segment lining to ensure the stability of the tunnel and to minimize ground deformation. If grouting is not sufficient to fill the gap between the segments and rock mass, hydraulic pressures occur in the void, which can negatively influence the stability of the tunnel. Recently the tendency to use TBM tunnelling method to replace the drill and blast(NATM) method is increasing. However, there are only a few studies of evaluation of backfill grout. This study evaluates the TBM tunnel backfill state using Impact-Echo(IE). 3-layers, segment-grout-rock mass, are simulated by FLAC 2D, FDM-based software. The signals obtained from numerical analysis and IE test are analyzed by Short-Time Fourier Transform(STFT) in time domain, frequency domain, and time-frequency domain. The result of this study can be used to evaluate the quality of backfill grouting in tail void.

Keywords: tunnel boring machine, backfill grout, impact-echo method, time-frequency domain analysis, finite difference method

Procedia PDF Downloads 266

Authors: Mico Kenshee C. Samarista, John Harvey V. Miranda, Janne Audrae Q. Lebosada, Josef Anton R. Benitez, Juan Miguel C. Rubio

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This research paper presents the development and evaluation of a web-based application designed to simplify the process of car rental services in the Philippines. As the demand for convenient and efficient access to rental car information grows, the need for a user-friendly platform becomes increasingly crucial. The web-based application serves as a comprehensive central hub, aggregating and organizing rental car listings from various reputable websites across the Philippines. By collecting essential data through surveys and usability testing, we assess the platform's effectiveness in simplifying the rental car selection process.

Keywords: web, application, car, services

Procedia PDF Downloads 89

Authors: Mehrdad Rezaei, Reza Haghmaram, Nima Amjadi

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This paper proposes an operating and cost optimization model for micro-grid (MG). This model takes into account emission costs of NOx, SO2, and CO2, together with the operation and maintenance costs. Wind turbines (WT), photovoltaic (PV) arrays, micro turbines (MT), fuel cells (FC), diesel engine generators (DEG) with different capacities are considered in this model. The aim of the optimization is minimizing operation cost according to constraints, supply demand and safety of the system. The proposed genetic algorithm (GA), with the ability to fine-tune its own settings, is used to optimize the micro-grid operation.

Keywords: micro-grid, optimization, genetic algorithm, MG

Procedia PDF Downloads 511

Authors: P. Jayaram, Prasoon Prasannan, N. K. Deepak, P. P. Pradyumnan

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Indium and Zirconium co doped zinc oxide (InZrZnO) thin films are prepared by chemical spray pyrolysis method on pre-heated quartz substrates. The films are subjected to vacuum annealing at 400ᵒC for three hours in an appropriate air (10-5mbar) ambience after deposition. X-ray diffraction, Scanning electron microscopy, energy dispersive spectra and photoluminescence are used to characterize the films. Temperature dependent electrical measurements are conducted on the films and the films exhibit exceptional conductivity at higher temperatures. XRD analysis shows that all the films prepared in this work have hexagonal wurtzite structure. The average crystallite sizes of the films were calculated using Scherrer’s formula, and uniform deformation model (UDM) of Williamson-Hall method is used to establish the micro-strain values. The dislocation density is determined from the Williamson and Smallman’s formula. Intense, broad and strongly coupled multiple photoluminescence were observed from photoluminescence spectra. PL indicated relatively high concentration defective oxygen and Zn vacancies in the film composition. Strongly coupled ultraviolet near blue emissions authenticate that the dopants are capable of inducing modulated free excitonic (FX), donor accepter pair (DAP) and longitudinal optical phonon emissions in thin films.

Keywords: PL, SEM, TCOs, thin films, XRD

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Authors: Riki H. Patel, Arpan Desia, Trushit Upadhayay

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The demand of compact antenna is ever increasing since the inception of wireless communication devices. In the age of wireless communication, requirement of miniaturized antennas is quite high. It is quite often that antenna dimensions are decided based on application based requirement compared to practical antenna constraints. The tradeoff in efficiency and other antenna parameters against to antenna size is always a debatable issue. The article presents detailed review of fundamentals of electrically small antennas and its potential applications. In addition, constraints and challenges of electrically small antennas are also presented in the article.

Keywords: bandwidth, communication, electrically small antenna, communication engineering

Procedia PDF Downloads 530

Authors: Hana Gebremariam Liliso

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This study investigates the factors contributing to the deterioration of thick asphalt pavements, such as rutting and cracking. We focus on the combined influence of traffic loads and pavement structure. This study uses a three-dimensional finite element model with a Mohr-Coulomb failure criterion to analyze the stress levels near the pavement's surface under realistic conditions. Our model considers various factors, including tire-pavement contact stresses, asphalt properties, moving loads, and dynamic analysis. This research suggests that cracking tends to occur between dual tires. Some key discoveries include the risk of cracking increases as temperatures rise; surface cracking at high temperatures is associated with distortional deformation; using a uniform contact stress distribution underestimates the risk of failure compared to realistic three-dimensional tire contact stress, particularly at high temperatures; the risk of failure is higher near the surface when there is a negative temperature gradient in the asphalt layer; and debonding beneath the surface layer leads to increased shear stress and premature failure around the interface.

Keywords: asphalt pavement, surface failure, 3d finite element model, multiaxial stress states, Mohr-Coulomb failure criterion

Procedia PDF Downloads 59

Authors: Aaron Huber, Manoj Karwa

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Floods, heat waves, drought, wildfires, tornadoes and other environmental disasters are a snapshot of looming national problems that can create increasing demands on the national grid. With nearly 500,000 school buses on the road and the environmental protection agency (EPA) providing nearly $1B for electric school buses, there is a solution for this national issue. Bidirectional batteries in electric school buses enable a future proof solution to sustain the power grid during adverse environmental conditions and other periods of high demand. School buses have larger batteries than standard electric vehicles. When they are not transporting students, these buses can spend peak solar hours parked and plugged into bi-directional direct current fast chargers (DCFC). A partnership with Highland Electric, Proterra and Rhombus enabled over 7 MWh of energy servicing Massachusetts and Vermont grids. The buses were part of a vehicle to grid (V2G) program with National Grid and Green Mountain Power that can charge an average American home for one month with a single bus. V2G infrastructure enables school systems to future proof their charging strategies, strengthen their local grids and can create additional revenue streams with their EV fleets. A bidirectional ecosystem with Highland, Proterra and Rhombus can enable grid resiliency or the ability to withstand power outages caused by excessive demands, natural disasters or rogue nation's attacks with no loss of service. A fleet of school buses is a standalone resilient asset that can be accessed across a city to keep its citizens safe without having any toxic fumes. Nearly 95% of all school buses across USA are powered by diesel internal combustion engines. Diesel exhaust has been classified as a human carcinogen, and it can lead to and exacerbate respiratory conditions. Bidirectional school buses and chargers enable energy justice by providing backup power in case of emergencies or high demand for marginalized communities and aim to make energy more accessible, affordable, clean, and democratically managed.

Keywords: V2G, vehicle to grid, electric buses, eBuses, DC fast chargers, DCFC

Procedia PDF Downloads 77

Authors: Ashwini Shripatwar, Mayur Biyani, Nikhil Rao, Rajendra Bodake, Sachin Sane

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This paper documents the correlation of valve cover sealing, cracking, and warpage Finite Element Modelling with observations on engine test development. The valve cover is a component mounted on engine head with a gasket which provides sealing against oil which flows around camshaft, valves, rockers, and other overhead components. Material nonlinearity and contact nonlinearity characteristics are taken into consideration because the valve cover is made of a composite material having temperature dependent elastic-plastic properties and because the gasket load-deformation curve is also nonlinear. The leakage is observed between the valve cover and the engine head due to the insufficient contact pressure. The crack is observed on the valve cover due to force application at a region with insufficient stiffness and with elevated temperature. The valve cover shrinkage is observed during the disassembly process on hot exhaust side bolt holes after the engine has been running. In this paper, an analytical approach is developed to correlate a Finite Element Model with the observed failures and to address the design issues associated with the failure modes in question by making design changes in the model.

Keywords: cracking issue, gasket sealing analysis, nonlinearity of contact and material, valve cover

Procedia PDF Downloads 142

Authors: Yan Pang, Xiang Wang, Zhaomiao Liu

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Droplet microfluidics, in which nanoliter to picoliter droplets acted as individual compartments, are common to a diverse array of applications such as analytical chemistry, tissue engineering, microbiology and drug discovery. The droplet generation in a simplified two dimension T-shape microchannel with the main channel width of 50 μm and the side channel width of 25 μm, is simulated to investigate effects of the forced fluctuation of the side wall on the droplet generation and flow. The periodic fluctuations are applied on a length of the side wall in the main channel of the T-junction with the deformation shape of the double-clamped beam acted by the uniform force, which varies with the flow time and fluctuation periods, forms and positions. The fluctuations under most of the conditions expand the distribution range of the droplet size but have a little effect on the average size, while the shape of the fixed side wall changes the average droplet size chiefly. Droplet sizes show a periodic pattern along the relative time when the fluctuation is forced on the side wall near the T-junction. The droplet emerging frequency is not varied by the fluctuation of the side wall under the same flow rate and geometry conditions. When the fluctuation period is similar with the droplet emerging period, the droplet size shows a nice stability as the no fluctuation case.

Keywords: droplet generation, droplet size, flow flied, forced fluctuation

Procedia PDF Downloads 282

Authors: Gang Li, Ghulam Mubashar Hassan, Arcady Dyskin, Cara MacNish

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Digital image correlation (DIC) is a contactless full-field displacement and strain reconstruction technique commonly used in the field of experimental mechanics. Comparing with physical measuring devices, such as strain gauges, which only provide very restricted coverage and are expensive to deploy widely, the DIC technique provides the result with full-field coverage and relative high accuracy using an inexpensive and simple experimental setup. It is very important to study the natural patterns effect on the DIC technique because the preparation of the artificial patterns is time consuming and hectic process. The objective of this research is to study the effect of using images having natural pattern on the performance of DIC. A systematical simulation method is used to build simulated deformed images used in DIC. A parameter (subset size) used in DIC can have an effect on the processing and accuracy of DIC and even cause DIC to failure. Regarding to the picture parameters (correlation coefficient), the higher similarity of two subset can lead the DIC process to fail and make the result more inaccurate. The pictures with good and bad quality for DIC methods have been presented and more importantly, it is a systematic way to evaluate the quality of the picture with natural patterns before they install the measurement devices.

Keywords: Digital Image Correlation (DIC), deformation simulation, natural pattern, subset size

Procedia PDF Downloads 419

Authors: Aymen H. Khalil, Ashraf M. Heniegal, Bassam A. Abdelsalam

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There are many problems related to cantilever slabs such as the time-dependent deformation, corrosion problems of steel reinforcement, and lack of experimental studies on the strength of strengthened cantilever slabs. This paper presents an investigation to evaluate the behavior of reinforced concrete cantilever slabs after strengthening with different techniques. Six medium scale specimens, divided into three groups, were tested along with a control slab. The first group consists of two specimens which were repaired and strengthened using reinforced concrete jacket above with and without shear connector bars, whereas the second group contained two slabs which were strengthened using two strips of two layers of glass fiber reinforced polymer (GFRP) covering 60% and 90% from the cantilever length. The last group involves two specimens strengthened with two steel plates. In one specimen, the steel plates were glued to the surface using epoxy resin. The second specimen, the steel plates were affixed to the concrete surface using expansion bolts. The loading was conducted in two phases. Firstly, the samples were subjected to 40% of the ultimate load of the control slab. Secondly, the specimens reloaded after being strengthened up to failure. The load-deflection, steel strain, concrete strain, failure mode, toughness, and ductility index are discussed in this paper.

Keywords: repair, strengthened, GFRP layers, reloaded, jacketing, cantilever slabs

Procedia PDF Downloads 199

Authors: Narayan Prasad Adhikari

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In Nepal, the crop residues have often been considered as one of the potential sources of energy to cope with prevailing energy crisis. However, the lack of systematic studies about production and various other competent uses of crop production is the main obstacle to evaluate net potential of the residues for energy production. Under this background, this study aims to assess the net annual availability of crop residues for energy production by undertaking three different districts with the representation of country’s three major regions of lowland, hill, and mountain. The five major cereal crops of paddy, wheat, maize, millet, and barley are considered for the analysis. The analysis is based upon two modes of household surveys. The first mode of survey is conducted to total of 240 households to obtain key information about crop harvesting and livestock management throughout a year. Similarly, the quantification of main crops along with the respective residues on fixed land is carried out to 45 households during second mode. The range of area of such fixed land is varied from 50 to 100 m2. The measurements have been done in air dry basis. The quantity for competitive uses of respective crop residues is measured on the basis of respondents’ feedback. There are four major competitive uses of crop residues at household which are building material, burning, selling, and livestock fodder. The results reveal that the net annual available crop residues per household are 4663 kg, 2513 kg, and 1731 kg in lowland, hill, and mountain respectively. Of total production of crop residues, the shares of dedicated fodder crop residues (except maize stalk and maize cob) are 94 %, 62 %, and 89 % in lowland, hill, and mountain respectively and of which the corresponding shares of fodder are 87 %, 91 %, and 82 %. The annual percapita energy equivalent from net available crop residues in lowland, hill, and mountain are 2.49 GJ, 3.42 GJ, and 0.44 GJ which represent 30 %, 33 %, and 3 % of total annual energy consumption respectively whereas the corresponding current shares of crop residues are only 23 %, 8 %, and 1 %. Hence, even utmost exploitation of available crop residues can hardly contribute to one third of energy consumption at household level in lowland, and hill whereas this is limited to particularly negligible in mountain. Moreover, further analysis has also been done to evaluate district wise supply-demand context of dedicated fodder crop residues on the basis of presence of livestock. The high deficit of fodder crop residues in hill and mountain is observed where the issue of energy generation from these residues will be ludicrous. As a contrary, the annual production of such residues for livestock fodder in lowland meets annual demand with modest surplus even if entire fodder to be derived from the residues throughout a year and thus there seems to be further potential to utilize the surplus residues for energy generation.

Keywords: crop residues, hill, lowland, mountain

Procedia PDF Downloads 472

Authors: Sandeep Sharma, Sarabjit Singh

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As per the user demand and growth trends of large free data the storage solutions are now becoming more challenge-able to protect, store and to retrieve data. The days are not so far when the storage companies and organizations are start saying 'no' to store our valuable data or they will start charging a huge amount for its storage and protection. On the other hand as per the environmental conditions it becomes challenge-able to maintain and establish new data warehouses and data centers to protect global warming threats. A challenge of small data is over now, the challenges are big that how to manage the exponential growth of data. In this paper we have analyzed the growth trend of big data and its future implications. We have also focused on the impact of the unstructured data on various concerns and we have also suggested some possible remedies to streamline big data.

Keywords: big data, unstructured data, volume, variety, velocity

Procedia PDF Downloads 548

Authors: Mecabih Zohra

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Water is such an important element of many manufacturing processes which that use a big amount of chemical substances, It is likely to cause it contamination of water returning to rivers by industrial discharged. These contaminants can be a high in suspended solid and chemical oxygen demand. In this study, urban wastewater of sidi bel abbes city (Algeria) was treated by adsorption using modified bentonite from Magnia (Algeria) by conducting batch experiments to investigate its equilibrium characteristics and kinetics. Purified bentonite is characterized by; CEC, XRF, BET, FITR, XRD, SEM and 27Al spectroscopy. The results showed the removal of suspended solids exceeds 98.47% and COD up to 99.52%, and regarding of sorption efficiencies (qm), the maximum COD sorption efficiencies (qm) calculated using the Langmuir model is 156.23, 64.47 and 17.19 mg/g respectively, for a pH range of 4 to 9.

Keywords: adsorption, bentonite, COD, wastewater

Procedia PDF Downloads 85

Authors: Mecabih Zohra

Abstract:

Water is such an important element of many manufacturing processes which that use a big amount of chemical substances, It is likely to cause it contamination of water returning to rivers by industrial discharged. These contaminants can be a high in suspended solid and chemical oxygen demand. In this study, urban wastewater of sidi bel abbes city (Algeria) was treated by adsorption using modified bentonite from Magnia (Algeria) by conducting batch experiments to investigate its equilibrium characteristics and kinetics. Purified bentonite is characterized by; CEC, XRF, BET, FITR, XRD, SEM and 27Al spectroscopy. The results showed the removal of suspended solids exceeds 98.47% and COD up to 99.52%, and regarding of sorption efficiencies (qm), the maximum COD sorption efficiencies (qm) calculated using the Langmuir model is 156.23, 64.47 and 17.19 mg/g respectively, for a pH range of 4 to 9.

Keywords: adsorption, bentonite, COD, wastewater

Procedia PDF Downloads 83

Authors: Eman Mohamed Ali Elalwani

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The Libyan heritage buildings are currently facing a number of crises that pose a threat to their structural integrity, functionality, and overall performance. One of the challenges pertains to the loss of community identity, which has arisen due to the lack of awareness and unconscious behavior of the residents. An additional issue arises from inadequate site management practices, including the implementation of modern techniques and innovative building materials that are incompatible with structural elements, resulting in the deformation of certain sections of the buildings. The security concerns of the city, along with the ongoing civil conflict, fostered a conducive environment for violations, resulting in the vandalism of certain monuments in the city. However, the degradation of this valuable heritage is mainly attributed to the city's neglect and pollution. The elevated groundwater level resulting from pollution has led to erosion in the building's foundations. Mitigating these negative consequences through strategic interventions and rehabilitation is required to preserve this treasure. In order to assist the local community in recovering from those crises, this paper stated a viable strategy for promoting preservation efforts that aimed at safeguarding the heritage sites while also providing guidance to decision-makers and the local community on how to avoid these crises, preserve, enhance, and recognize the significance of the Libyan heritage.

Keywords: cultural heritage, historical buildings, Tripoli’s old city, Red Castle, crises, preservation

Procedia PDF Downloads 125

Authors: Ichiro Takahashi

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One of the major assumptions of mainstream macroeconomics is the path independence of capital stock. This paper challenges this assumption by employing an agent-based approach. The simulation results showed the existence of multiple "quasi-steady state" equilibria of the capital stock, which may cast serious doubt on the validity of the assumption. The finding would give a better understanding of many phenomena that involve hysteresis, including the causes of poverty. The "market-clearing view" has been widely shared among major schools of macroeconomics. They understand that the capital stock, the labor force, and technology, determine the "full-employment" equilibrium growth path and demand/supply shocks can move the economy away from the path only temporarily: the dichotomy between the short-run business cycles and the long-run equilibrium path. The view then implicitly assumes the long-run capital stock to be independent of how the economy has evolved. In contrast, "Old Keynesians" have recognized fluctuations in output as arising largely from fluctuations in real aggregate demand. It will then be an interesting question to ask if an agent-based macroeconomic model, which is known to have path dependence, can generate multiple full-employment equilibrium trajectories of the capital stock in the super-long run. If the answer is yes, the equilibrium level of capital stock, an important supply-side factor, would no longer be independent of the business cycle phenomenon. This paper attempts to answer the above question by using the agent-based macroeconomic model developed by Takahashi and Okada (2010). The model would serve this purpose well because it has neither population growth nor technology progress. The objective of the paper is twofold: (1) to explore the causes of long-term business cycle, and (2) to examine the super-long behaviors of the capital stock of full-employment economies. (1) The simulated behaviors of the key macroeconomic variables such as output, employment, real wages showed widely diversified macro-economies. They were often remarkably stable but exhibited both short-term and long-term fluctuations. The long-term fluctuations occur through the following two adjustments: the quantity and relative cost adjustments of capital stock. The first one is obvious and assumed by many business cycle theorists. The reduced aggregate demand lowers prices, which raises real wages, thereby decreasing the relative cost of capital stock with respect to labor. (2) The long-term business cycles/fluctuations were synthesized with the hysteresis of real wages, interest rates, and investments. In particular, a sequence of the simulation runs with a super-long simulation period generated a wide range of perfectly stable paths, many of which achieved full employment: all the macroeconomic trajectories, including capital stock, output, and employment, were perfectly horizontal over 100,000 periods. Moreover, the full-employment level of capital stock was influenced by the history of unemployment, which was itself path-dependent. Thus, an experience of severe unemployment in the past kept the real wage low, which discouraged a relatively costly investment in capital stock. Meanwhile, a history of good performance sometimes brought about a low capital stock due to a high-interest rate that was consistent with a strong investment.

Keywords: agent-based macroeconomic model, business cycle, hysteresis, stability

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Authors: Carine Muster, Prina Howald Erika

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Today's ice rinks are important energy consumers for the production and maintenance of ice. At the same time, users demand that the other rooms should be tempered or heated. The building complex must equally provide cooled and heated zones, which does not translate as carbon-zero ice rinks. The study provides an analysis of how the civil engineering sector can significantly impact minimizing greenhouse gas emissions and optimizing synergies across an entire ice rink complex. The analysis focused on three distinct aspects: the layout, including the volumetric layout of the premises present in an ice rink; the materials chosen that can potentially use the most ecological structural approach; and the construction methods based on innovative solutions to reduce carbon footprint. The first aspect shows that the organization of the interior volumes and defining the shape of the rink play a significant role. Its layout makes the use and operation of the premises as efficient as possible, thanks to the differentiation between heated and cooled volumes while optimising heat loss between the different rooms. The sprayed concrete method, which is still little known, proves that it is possible to achieve the strength of traditional concrete for the structural aspect of the load-bearing and non-load-bearing walls of the ice rink by using materials excavated from the construction site and providing a more ecological and sustainable solution. The installation of an empty sanitary space underneath the ice floor, making it independent of the rest of the structure, provides a natural insulating layer, preventing the transfer of cold to the rest of the structure and reducing energy losses. The addition of active pipes as part of the foundation of the ice floor, coupled with a suitable system, gives warmth in the winter and storage in the summer; this is all possible thanks to the natural heat in the ground. In conclusion, this study provides construction recommendations for future ice rinks with a significantly reduced energy demand, using some simple preliminary design concepts. By optimizing the layout, materials, and construction methods of ice rinks, the civil engineering sector can play a key role in reducing greenhouse gas emissions and promoting sustainability.

Keywords: climate change, energy optimization, green building, sustainability

Procedia PDF Downloads 67

Authors: Zhikang Rong

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The 4th industrial revolution has introduced technologies like interconnectivity, machine learning, and real-time big data analytics that improve operations and business efficiency. This paper examines how these advancements have led to a concentration of wealth, specifically among the top 1%, and investigates whether this wealth provides value to society. Through analyzing impacts on employment, productivity, supply-demand dynamics, and potential externalities, it is shown that successful businesspeople, by enhancing productivity and creating jobs, contribute positively to long-term economic growth. Additionally, externalities such as environmental degradation are managed by social entrepreneurship and government policies.

Keywords: wealth creation, employment, productivity, social entrepreneurship

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Authors: Joseph E. Estevez, Mahdi Ghazizadeh, James G. Ryan, Ajit D. Kelkar

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Radiation shielding is an obstacle in long duration space exploration. Boron Nitride Nanotubes (BNNTs) have attracted attention as an additive to radiation shielding material due to B10’s large neutron capture cross section. The B10 has an effective neutron capture cross section suitable for low energy neutrons ranging from 10-5 to 104 eV and hydrogen is effective at slowing down high energy neutrons. Hydrogenated BNNTs are potentially an ideal nanofiller for radiation shielding composites. We use Molecular Dynamics (MD) Simulation via Material Studios Accelrys 6.0 to model the Young’s Modulus of Hydrogenated BNNTs. An extrapolation technique was employed to determine the Young’s Modulus due to the deformation of the nanostructure at its theoretical density. A linear regression was used to extrapolate the data to the theoretical density of 2.62g/cm3. Simulation data shows that the hydrogenated BNNTs will experience a 11% decrease in the Young’s Modulus for (6,6) BNNTs and 8.5% decrease for (8,8) BNNTs compared to non-hydrogenated BNNT’s. Hydrogenated BNNTs are a viable option as a nanofiller for radiation shielding nanocomposite materials for long range and long duration space exploration.

Keywords: boron nitride nanotube, radiation shielding, young modulus, atomistic modeling

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Authors: Ali A. Al-Jazaairry, Tahsin T. Sabbagh

Abstract:

Presence of cavities in soil predictably induces ground deformation and changes in soil stress, which might influence adjacent existing pile foundations, though the effect of twin cavities on a nearby pile needs to be understood. This research is an attempt to identify the behaviour of piles subjected to axial load and embedded in cavitied clayey soil. A series of finite element modelling were conducted to investigate the performance of piled foundation located in such soils. The validity of the numerical simulation was evaluated by comparing it with available field test and alternative analytical model. The study involved many parameters such as twin cavities size, depth, spacing between cavities, and eccentricity of cavities from the pile axis on the pile performance subjected to axial load. The study involved many cases; in each case, a critical value has been found in which cavities’ presence has shown minimum impact on the behaviour of pile. Load-displacement relationships of the affecting parameters on the pile behaviour were presented to provide helpful information for designing piled foundation situated near twin underground cavities. It was concluded that the presence of the cavities within the soil mass reduces the ultimate capacity of pile. This reduction differs according to the size and location of the cavity.

Keywords: axial load, clay, finite element, pile, twin cavities, ultimate capacity

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Authors: Zafar Iqbal Zafar, Abdul Waheed

Abstract:

The Capital Development Authority (CDA) Ordinance 1960 requires CDA to acquire land for the provision of housing in Islamabad. However, the pace of residential development was slow and the demand for housing was increasing rapidly. To resolve the growing housing problem, CDA involved the private sector in the development of housing schemes. Detailed bye-laws for regulation of private housing schemes were prepared and these bylaws were called “Modalities & Procedures”. This paper explains how the Modalities and Procedures of CDA have been successful in regulating the development of private housing schemes in Islamabad.

Keywords: housing schemes, master plan, development works, zoning regulations

Procedia PDF Downloads 201

Authors: Nishita Jaiswal, Apoorv Mohan Satpute

Abstract:

The increasing demand for efficient, cost-effective motor control systems in the automotive industry has driven the need for advanced, highly optimized control algorithms. Field-Oriented Control (FOC) has established itself as the leading approach for motor control, offering precise and dynamic regulation of torque, speed, and position. However, as energy efficiency becomes more critical in modern applications, implementing FOC on low-power, cost-sensitive microcontrollers pose significant challenges due to the limited availability of computational and hardware resources. Currently, most solutions rely on high-performance 32-bit microcontrollers or Application-Specific Integrated Circuits (ASICs) equipped with Floating Point Units (FPUs) and Hardware Accelerated Units (HAUs). These advanced platforms enable rapid computation and simplify the execution of complex control algorithms like FOC. However, these benefits come at the expense of higher costs, increased power consumption, and added system complexity. These drawbacks limit their suitability for embedded systems with strict power and budget constraints, where achieving energy and execution efficiency without compromising performance is essential. In this paper, we present an alternative approach that utilizes optimized data representation and computation techniques on a 16-bit microcontroller without FPUs or HAUs. By carefully optimizing data point formats and employing fixed-point arithmetic, we demonstrate how the precision and computational efficiency required for FOC can be maintained in resource-constrained environments. This approach eliminates the overhead performance associated with floating-point operations and hardware acceleration, providing a more practical solution in terms of cost, scalability and improved execution time efficiency, allowing faster response in motor control applications. Furthermore, it enhances system design flexibility, making it particularly well-suited for applications that demand stringent control over power consumption and costs.

Keywords: field-oriented control, fixed-point arithmetic, floating point unit, hardware accelerator unit, motor control systems

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Authors: Sao-Jeng Chao, Wen-Cheng Chen, Wei-Humg Lu

Abstract:

In order to prevent encountering unpredictable factors, geotechnical engineers always conduct numerical analysis for braced excavation design. Simulation work in advance can predict the response of subsequent excavation and thus will be designed to increase the security coefficient of construction. The parameters that are considered include geological conditions, soil properties, soil distributions, loading types, and the analysis and design methods. National Ilan University is located on the LanYang plain, mainly deposited by clayey soil and loose sand, and thus is vulnerable to external influence displacement. National Ilan University experienced a construction of braced excavation with a complete program of monitoring excavation. This study takes advantage of a one-dimensional finite element method RIDO to simulate the excavation process. The predicted results from numerical simulation analysis are compared with the monitored results of construction to explore the differences between them. Numerical simulation analysis of the excavation process can be used to analyze retaining structures for the purpose of understanding the relationship between the displacement and supporting system. The resulting deformation and stress distribution from the braced excavation cab then be understand in advance. The problems can be prevented prior to the construction process, and thus acquire all the affected important factors during design and construction.

Keywords: excavation, numerical simulation, RIDO, retaining structure

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Authors: J. Omer, H. Haroglu

Abstract:

Base enlargement in piles was invented to enhance pile resistance in downward loading, but the contribution of an enlarged base to the lateral load resistance of a pile has not been fully exploited or understood. This paper presents a laboratory investigation of the lateral capacity and deformation response of small-scale steel piles with enlarged bases installed in dry sand. Static loading tests were performed on 24 model piles having different base-to-shaft diameter ratios. The piles were installed in a box filled with dry sand, and lateral loads were applied to the pile tops using a pulley system. The test piles had shaft diameters of 20 mm, 16 mm, and 10 mm; base diameters of 900 mm, 700 mm, and 500 mm. As a control, a pile without base enlargement was tested to allow comparisons with the enlarged base piles. Incremental maintained loads were applied until pile failure approached while recording pile head deflections with high-precision dial gauges. The results showed that the lateral capacity increased with an increase in base diameter, albeit by different percentages depending on the shaft diameters and embedment length in the sand. There was always an increase in lateral capacity with increasing embedment length. Also, it was observed that an enlarged pile base had deflected less at a given load when compared to the control pile. Therefore, the research demonstrated the benefits of lateral capacity and stability of enlarging a pile base.

Keywords: pile foundations, enlarged base, lateral loading

Procedia PDF Downloads 155