bluuebunny/crossref_metadata_2025 huggingface dataset:
Ocean and atmosphere influence on the 2015 European heatwave
Authors: Mecking J V , Drijfhout S S , Hirschi J J-M , Blaker A T
Published: October 2019

During the summer of 2015, central Europe experienced a major heatwave that was preceded by anomalously cold sea surface temperatures (SSTs) in the northern North Atlantic. Recent observation-based studies found a correlation between North Atlantic SST in spring and European summer temperatures, suggesting potential for predictability. Here we show, by using a high-resolution climate model, that ocean temperature anomalies, in combination with matching atmospheric and sea-ice initial conditions were key to the development of the 2015 European heatwave. In a series of 30-member ensemble simulations we test different combinations of ocean temperature and salinity initial states versus non-initialised climatology, mediated in both ensembles by different atmospheric/sea-ice initial conditions, using a non-standard initialisation method without data-assimilation. With the best combination of the initial ocean, and matching atmosphere/sea-ice initial conditions, the ensemble mean temperature response over central Europe in this set-up equals 60% of the observed anomaly, with 6 out of 30 ensemble-members showing similar, or even larger surface air temperature anomalies than observed.
What buildings policy might look like if we took climate change seriously
Authors: Fawcett Tina , Topouzi Marina
Published: October 2019

In 2018, the Intergovernmental Panel on Climate Change released its report on the impacts of global warming of 1.5°C. It called for “rapid, far-reaching and unprecedented changes in all aspects of society” to reduce the risks of increasing climate change. Energy use in buildings is one of the key contributors to greenhouse gas emissions in the UK and EU. Detailed policies to support high standards in new build and acceleration of ambitious retrofit are a necessary part of any serious response to climate change.

This paper begins with a description of key UK policies on energy use in the buildings, and future UK government plans as expressed in the Clean Growth Strategy. It analyses the direction of travel, and looks at the rate of change compared with what will be required to rapidly reduce carbon emissions from the sector. Current buildings policies are insufficient to meet the challenge of climate change. Both positive and negative examples of changes in policy are presented.

A new conceptualization of the contribution of energy demand to delivering net zero goals, developed by CREDS, is introduced. In addition, key characteristics of the buildings sector and its energy use are put forward. Bringing together the role of energy demand, these characteristics of buildings, and the broader literature on buildings and energy policy, we have set out an exploratory set of guidelines for developing policy to reduce carbon emissions from buildings further, faster and more flexibly. These are classified into the guiding principle, approaches to policy creation, expanding the boundaries of policies and focus on quality. These should form the basis for further discussion.

If policy were designed as if we took climate change seriously, according to the guidelines developed, what would this mean for buildings? Fundamentally it would require a momentous change in the culture of construction, so that what is valued moves beyond design, aesthetics and functionality, to include low carbon and highly efficient performance. New targets and approaches to delivering them are required – and this paper contributes to thinking about both.
Energy-related policy in the housing sector of Bulgaria: in search for a meeting point of social and technical dimensions
Authors: Dimitrova E , Petrova-Tasheva M , Mutafchiiska I , Burov A
Published: October 2019

Understanding the way in which a policy framework put into action supports or hampers stakeholders’ energy-related action in the field of housing renovation could provide meaningful insight on needed respect for stakeholders’ needs, expectations, motivations and capacity for action. The paper presents a study undertaken on the case of Bulgaria as part of ongoing ECHOES research project (EU-funded under the Horizon 2020 Program). It discusses the complex challenges faced in linking policy and technical to social and cultural considerations in renovating the existing residential stock in Bulgaria while meeting energy-efficiency requirements with an explicit focus on predominant apartment buildings in multiple ownership. The refurbishment process requires, on one hand, considerable investment, which is in most cases hardly accessible for the homeowners; on the other hand, collective decision-making with numerous stakeholders involved, often with diverse social and economic status. The presented two national case studies illustrate two alternative approaches applied – one searching to benefit from the national energy market peculiarities, and the other taking the opportunities provided by European and national grant schemes introduced in the country. Based on contacts and semi-structured interviews with various actors involved in the two initiatives, the dynamics of the situation throughout the projects’ life cycle sand and in the longer term and the changing personal estimations of costs and benefits are analysed. Conclusions are drawn about the importance of continuity in implemented energy-related policies. The authors claim that specific paths to EU energy policy goals under varying economic, technical and sociocultural context should be well continually informed by comprehensive interdisciplinary research.
Passive Strategies for Buildings in Hot and Dry Climates: Optimisation of Informal Apartment Blocks in Cairo
Authors: Vignola Gionatan , Kiracofe Ryan , Dietrich Udo
Published: October 2019

Cairo’s dry and hot climate leads to challenges related to health, thermal comfort and energy consumption that its urban dwellers encounter daily. The informal apartment blocks in which most of the Cairene households live are generally poorly insulated against external heat gains, hardly shaded and poorly ventilated. Furthermore, especially during summer, about one-fifth of households experience constant power interruptions. This research shows to what extent it is possible, by using passive strategies, to optimise the architecture of informal apartment blocks, to meet the end user’s thermal comfort expectations while being energy and environmentally sound. By using Primero, an EnergyPlus based software, existing informal and traditional Cairenes buildings have been modelled, and thermal comfort and energy performance simulated and compared. Performance of informal buildings has been optimised and improved by using passive strategies. This has been possible by changing the structure of the building (adding an overhang), and by experimenting with the use of different materials for external wall constructions (all of which available in Egypt).
3D built-environment attributes and household road traffic noise exposure in Hong Kong
Authors: Guo Mengdi , Huang Jianxiang , Yuxuan Ni Michael
Published: October 2019

Road traffic noise is an environmental health hazard in Hong Kong and other high-density cities. The dense built environment modifies noise propagation, reflects, absorbs or diffracts sound depending on building morphology, road configuration, and open space layout, etc. Mitigation of urban traffic noise is of growing concerns to planning and design practitioners. Existing assessment methods are limited in reliably accounting for localized variations in noise exposure associated with a high-density city. The aim of this research is to 1) develop a 3D database of road traffic noise exposure for a large number of households in a high-density city; 2) explore the linkages between built environment attributes and road traffic noise exposure. A 3D built environment database was constructed for Hong Kong using building geometries, topography and urban traffic noise data. Window coordinates for each household were extracted using address and building floor plans. Computer simulation was conducted to determine traffic noise exposure at window locations using CadnaA for a random sample of 8,158 households across the city. Results revealed that 76.3% of the households are exposed to excessive road traffic noise by WHO standards. Household traffic noise exposure are significantly associated with proximity to secondary road, story-level of the flat, and other urban form attributes. The 3D database is of value for public health research in relation to noise and urban noise mitigation measures. The next step is to develop an efficient and reliable simulation tool to support planning and design decisions in traffic noise mitigation.
Communicating innovations: examples from smart technology retrofits
Authors: Darby S J
Published: October 2019

The importance of effective feedback loops during and after building retrofits is well-established. Good communications between designers, practitioners and building users typically lead to better outcomes for users and can allow designers, investors and builders to learn from experience.

Where ‘smart’ retrofits are concerned – that is, introduction of ICT for more sophisticated control and new functions such as demand response – it can seem as though the aim is a friction-free transfer of activity and learning from humans to machines. In such a scenario, the complexities of real-life routines and activities are typically minimised or ignored, along with the need for time and effort to put into sense-making and adaptation. The paper argues that this is unhelpful at best. Drawing on the author’s involvement in evaluating three contrasting programmes, it illustrates how smart refurbishment is an exercise in which ‘smartness’ is distributed between technologies and humans; one in which we can expect some emergent (i.e. unpredictable) outcomes. The three case studies, at different scales, are:

• the rollout of smart meters in Great Britain, a large-scale infrastructure refurbishment;

• ‘smartening’ domestic storage heaters and water heaters, a retrofit exercise in homes;

• ‘smartening’ electricity demand in a community – small-scale system upgrade.

These programmes show the significance of different types of communication in sociotechnical systems as they incorporate smart technologies. Thematic analysis indicates three ways of categorising communication during these processes: between technologies (connectivity), between technologies and people (controls), and between people (care). As buildings become more closely integrated into energy systems, for example via on-site generation, demand response and heat networks, these categories can be useful when designing, implementing and evaluating smart refurbishment.
Agent-Based Modelling of Occupants’ Clothing and Activity Behaviour and Their Impact on Thermal Comfort in Buildings
Authors: Zhang Anxiao , Huang Qiong , Du Yiming , Zhen Qi , Zhang Qi
Published: October 2019

This paper proposes a new agent-based approach to model the clothing and activity behaviour of occupants in buildings. An autonomous agent is created to interact with the surrounding thermal environment and make decisions based on its comfort level. The agent-based behaviour model was implemented by MATLAB and was linked with building energy simulation program EnergyPlus via Building Controls Virtual Test Bed (BCVTB) and MLE+. A simulation experiment was conducted to see how an agent adapts to the dynamic thermal changes in different seasons and how it affects the annual thermal comfort. Obvious variation in the predicted annual discomfort time can be observed when using the agent-based method compared with a traditional commonly used method with static parameters. The paper concludes with a discussion of the model’s current limitations and possibilities for future development.
The relationship between thermal environments and clothing insulation for rural low-income residents in China in winter
Authors: Zhao Wei , Chow David , Sharples Steve
Published: October 2019

China is developing rapidly, but there is an obvious imbalance in the development level between urban and rural areas. Differences in economics, living conditions and life style contribute to differences in indoor thermal environments, and may result in differences in the perceptions of thermal comfort between urban and rural areas. Clothing insulation as one of the most important parameters that affect thermal comfort is studied in this research. A field study is conducted in the rural areas of Lankao, China. A total of 384 valid samples were acquired. 54.97% researched houses suffered extreme cold indoor temperatures between 2°C and 6°C. Clothing insulation value of researched population is significantly larger than in other research. Clothing insulation value of female is significantly larger than that of male. It was also found that clothing insulation value correlates positively with age, that clo grow with the increase of age significantly. 7-days running mean outdoor temperature was selected from four temperature indices to predict clothing insulation value. Clo value is negatively correlated with 7-days RM outdoor temperature. But, the slope is quite small in such an extreme cold condition. A case study was conducted to estimate influence of adaptive clothing insulation on heating energy consumption (from Nov. to Mar.). Results show that 863 heating hours are reduced by using adaptive clothing insulation model. The total Heating Degree Hours (HDH) is reduced from 6445 to 1367 by 78.8% which means the same percentage of heating energy conservation. Besides, this case study also concluded that “adaptive clothing insulation model” has higher influence on heating energy consumption in transition season.
Residential building energy performance evaluation for different climate zones
Authors: Albogami S M , Boukhanouf R
Published: October 2019

The building sector in the Kingdom of Saudi Arabia accounts for a large proportion of energy consumption. This paper investigates energy consumption in residential type A villa buildings constructed by the Ministry of Housing. The study specifically investigates energy consumption of a case building in three climate zones of the country identified in the KSA Building Code (SBC-602E). The software package IES-ve was used to simulate power consumption of the case building taking into account the climate characteristics of each zone. In total 6 cities were considered from the three zones to evaluate and compare annual and monthly power consumption loads of the building. It was found that there is some distinction of energy consumption for heating and cooling in the three zones (e.g., peak monthly power energy consumption for cooling varied from 6.371 MWh in Riyadh (zone1) to 1.663 MWh in Abha (zone3) and no heating requirement for Jaddah (zone 1) while Turaif (zone 3) heating consumption is 23.835 MWh) however, further work is required to identify clearer the climate specifications within each zone to address the excess energy consumption of this type of buildings.
A Review of the Existing Residential Building Retrofit in Tianjin, China
Authors: Liu Y S , Liu C H , Li W
Published: October 2019

Tianjin, situates 120 km southeast of the capital city Beijing, is the largest open coastal city in northern China and has high economic status. From the beginning of the 20th century, the municipal government has done a lot on residential building retrofit. In China, the policies as well as standards of local governments play an important role in guiding and supporting the building industry. This paper clarify the characteristics of the existing residential buildings, and attempts to review the policies, standards and retrofit pilot projects implemented by governments since the beginning of 20th century in Tianjin. Four stages of retrofit process toward residential buildings in Tianjin are indicated: reconstruction of shanty housing, retrofit of basic function including building facade beautification, outdoor environment update and balcony reinforce, energy saving retrofit and comprehensive retrofit based on sustainable conception. In each stage, policies, retrofit principles and typical cases are analysed. We also shows that lots of retrofit technologies have been applied which can reduce energy consumption effective and make living environment more comfortable. But it also has many problems of residential retrofit, such as lack of local standards and financial strategy. Meanwhile, the trend of retrofit is predicted, which is based on sustainable concept, aimed at building performance, integrated with environmental protection, energy saving and high efficiency. At last, some suggestions are also presented for existing residential buildings retrofit in Tianjin.
A parametric analysis of the influence of wind speed and direction on the thermal comfort performance of a Passive Downdraught Evaporative Cooling (PDEC) system – field measurements from a Saudi Arabian library
Authors: Alshenaifi M A , Sharples S
Published: October 2019

Building energy consumption in the desert climate of Saudi Arabia is dominated by cooling demand. Electricity for this cooling is generated predominantly from finite fossil fuel reserves. To improve resource efficiency and decrease carbon emissions, reducing this demand by using more passive cooling approaches is desirable. One system is the passive downdraught evaporative cooling (PDEC) tower. PDEC captures hot, dry winds at the top of a tower and then cools the air by passing it through or over water. This cooler air then flows out from the base of the tower into the building. In this study, a PDEC system in a small Saudi public library was monitored for two summer months. A key aim of this study was to investigate the relationship between local wind speed and direction and the performance of the PDEC towers. A thermal comfort analysis investigated the acceptability limits of indoor temperature using the adaptive thermal comfort model. A parametric analysis of the wind effects was conducted by grouping wind data in to ranges of wind speed and direction and then correlating them against environmental conditions in the library. The results indicated that the PDEC towers could deliver significant cooling for library users. However, the towers’ effectiveness was influenced by changes in wind speed, and in a counter intuitive way – stronger wind speeds tended to reduce the tower cooling efficiency.
The Cooling Efficiency of Urban Greenery Coverage in a High-density City
Authors: Ouyang Wanlu , Eniolu Morakinyo Tobi , Ng Edward
Published: October 2019

Urban greenery especially trees has been identified as one of the most effective measures for urban climate moderation through the mechanism of evaporative cooling and shading. For subtropical high-density cities like Hong Kong, intense heat stress arises from the compact urban form, poor ventilation, and the high percentage of impervious urban cover. Thus, concerted actions are being taken to harness the cooling potential of urban greenery for improved microclimate. However, the cooling effects of urban greenery vary based on multiple factors, including background climates, urban morphology, anthropogenic heat emission, vegetation types and quantity, etc. This study aims at quantifying and comparing the cooling efficiency of different urban greenery coverage for a typical residential neighbourhood in Hong Kong. The questions guiding our research are: what is the relationship between tree coverage and ambient environment, including air temperature and thermal comfort during a typical summer day in the selected neighbourhood? To achieve this objective, we employed a previously validated ENVImet model setting of a typical summer day to conducted parametric studies of cooling benefit of variable tree coverage ratio from 0 to 30% at the interval of 2% on a typical summer day. The results verified the greenery had a higher cooling potential during period of maximum temperature than the whole diurnal time, 1 °C and almost 0.8 °C respectively for air temperature. This study also showed that increasing greenery coverage indeed lowers diurnal temperatures, but this relationship is logarithmic instead of linear. The ratio of change in cooling effects to greenery increase and then decreased gradually. Between the coverage ratio of 8%-35%, the cooling potential would be underestimated in a linear relationship. Greenery measures may lead to ineffective results if greening principles have not been comprehensive understood, such as greenery abundance, composition and types. The present study allows urban planners and managers to understand more in greenery amount for urban micro-climate in high-density cities.
Simulation-Informed Urban Design: Improving Urban Microclimate in Real-World Practice in a High Density City.
Authors: Huang Jianxiang , Hao Tongping , Shan Hou Shan , Jones Phil
Published: October 2019

In many dense cities, urban heat and the interaction of buildings with their immediate urban environment emerges as a pressing issue due to growing urban heat island effect and climate change. Informed evidence based design decisions to mitigate heat stress becomes a priority for urban planning and design practitioners. The aim of the study is to develop informed design and development decisions using computer simulation tools concerning urban microclimate performance. In this study, academic researchers have worked with industrial partners in an urban renewal project in Hong Kong’s high density urban area. In-house developed simulation software such as CityComfort+ and HTB2-Virvil were applied to assess urban microclimate conditions and risks of pedestrian thermal stress throughout key seasons. Simulation results were provided as feedback to project designers and managers at early stage, allowing timely design modification to improve performance while maintaining code compliance and design and fiscal priorities. The procedure is iterative until performance attributes converge. Preliminary results show that the informed design can deliver significant microclimate benefits compared with “business-as-usual scenarios”. By shaping building mass, orientation, and strategic placement of shading and vegetation, the improved design is expected to reduce summer-time outdoor heat stress by 1°C measured in UTCI equivalent temperature, thus bringing the average conditions for the hot season into the “comfort zone” for the local community. Energy simulation can predict overall energy demand and the potential for renewable energy supply at an urban scale. The simulation-designer workflow shows promising potentials to improve urban microclimate performance of design outcomes and the potential for zero carbon urban blocks. The early-stage action, forward-looking partnership, and computing efficiency of the simulation tools are the keys.
A feasibility study to evaluate the potential replication of an energy positive house in the UK
Authors: Li X , Patterson J , Coma Bassas E , Jones P
Published: October 2019

This paper presents an evaluation of the economic and technical feasibility of a renewable-led low carbon house in the UK. A holistic systems-based approach to achieve energy positive house has been taken. Long-term economic and technical feasibility analysis have been carried out based on a validated thermal and energy model of the house. The economic analysis employs the Return on Investment (ROI) method and considers changes to government financial support and technology progress over time. Results show that the extra investment on the house, compared with that for building a standard social house of similar size, can be paid back within the system lifespan under both the old Feed-in Tariff and its proposed replacement with reduced financial support. Variants examined in the technical feasibility analysis include housing type, orientation and location. Results show that the house can be replicated to achieve an energy positive performance for all variant combinations. Among the variants, location has the highest impact on building performance including annual electricity import, CO2 emission and electricity self-sufficient ratio, with South UK performing better than North UK. This implies that more efficient or advanced technologies would be needed to achieve similar building or system performance in areas of unfavourable climate. The outcome of the research has demonstrated the affordability of the energy positive house, and the technical feasibility of its replication with different housing types, orientations and locations in the UK. This study supports the wide scale replication of this affordable systems-based approach in domestic building design and construction when incorporating appropriate technologies.
Assessment of carbon foot print of Jaffna Town, Sri Lanka
Authors: Raveendran S , Srikaran V
Published: October 2019

Jaffna town is one of the emerging urban centers in Northern Sri Lanka which attract more people, resources and activities in the post war scenario. This study assesses the carbon foot print of the town. Cities play a key role to top up greenhouse gases into the atmosphere worldwide which lead to global warming and consequent climate change and related impacts. The carbon footprint of Jaffna town has not been assessed yet and the awareness of low carbon development is not common in the development domain which are essential to make decisions to carry out development consistent with Sustainable Development Goals. The purpose of the research to assess the gross carbon emission of Jaffna town and sectoral composition of the emission. The study shows that the city emits 312,096,821 Kg Co2e per day. More emission comes from domestic activities which account for 60%and second largest emission comes from transport sector. Nearly 60 %of the commuters are using private vehicles that account for nearly 20%of the total emission. Among the domestic emission, light and ventilation consume more energy than other uses. Solid waste management also contributes to emit nearly 6-10 %of the emission of the city. More houses consume relatively higher energy for light and ventilation because of the poor design of house that do not utilize the natural light and ventilation. The study suggest that the building design must adhere to the low carbon building designs which is not present in Jaffna. Appropriate building design that minimize the energy consumption need to formulated and implemented. Use of centralized air conditioning system in public building will minimize the energy consumption compared to distributed system. Integrated waste management system and sanitary land fill facilities will minimize the emission from solid waste disposal. Suitable urban design will encourage walking and cycling of residents and commuters. Deliberate planning of routes and facilities of public transport will promote the use of public transport between Jaffna and other suburban towns in the Northern Region.
Burning rate of polyurethane composite propellant with energetic nano-composite additives
Authors: Tawfik Sayed , Saleh Ahmed , Elbeih Ahmed
Published: October 2019

In this study, some improvements in the burning rate of hydroxyl-terminated polybutadiene (HTPB) based composite propellant was performed by introducing innovative fast burning energetic Al-Cu nanocomposite s (ACNs). By comparison with the reference composite propellant (based on nano-Al), the results showed the effectiveness of ACNs to improve the characteristics of HTPB composite propellant. The concentration effect of ANCs on the characteristics of HTPB propellant and the possibility of achieving further performance enhancement were studied. The main results have indicated that ACNs based propellants have achieved improvements in the combustion heat, burning rate, ignitability, and mechanical properties.
Multivariable flight controller design for ultrastick-25e UAV
Authors: Ashry Mahmoud M.
Published: October 2019

Ultrastick-25e is an Unmanned Aerial Vehicle (UAV) invented by university of Minnesota. Its controller was designed with conventional PI controller in both longitudinal and lateral channels. Throughout this paper, four control techniques are purposed for controlling the unmanned fixed-wing plane (Ultrastick-25e). These controllers are genetically tuned PI and PID, fuzzy like PI, and fuzzy like PD controllers. These controllers are utilized to control both longitudinal and lateral channels for the linear and nonlinear model of the Ultrastick-25e. The four controllers improve the system response of the UAV. Every controller passes the system robustness evaluation including the disturbance rejection and the noise attenuation capabilities. Furthermore, robustness is evaluated for model uncertainties using the nonlinear model. The essential contribution in this paper is utilizing the fuzzy logic controller for the unmanned fixed-wing Ultrastick-25e. The simulation results analysis assure the superiority of the two fuzzy logic controllers compared with the genetically tuned PI and PID controllers.
LFM-PC Radar Evaluation in Presence of Jamming using SystemVue
Authors: Soliman Mohamed Samir Abdel Latif , Mansour A.
Published: October 2019

Pulse Compression (PC) radars become; now a day; are the most commonly used in a lot of military applications. This is due to its capability to resolve the problem of designing long range radar with excellent range resolution. Also, it provides additional processing gain that enhances radar detection capability. Moreover, Pulse compression is considered as an electronic counter countermeasures (ECCM) capability. It provides the radar with a good immunity against different jamming techniques. There are a lot of types of PC waveforms. Linear Frequency Modulated (LFM) signals are the most tolerant to high Doppler shifts. This is why LFM-PC radars are widely utilized with high speed targets. However, the literature lacks a simulation model to evaluate the detection performance of LFM-PC radar in presence of different noise jamming techniques. This paper introduces a typical simulation model for LFM-PC search radar using SystemVue. The simulated model allows the studying of the PC radar performance with different jamming techniques. Also, the optimum jamming technique; from electronic warfare point of view; is explored.
Black-box modelling of gas turbine engine’s electrohydraulic fuel metering system.
Authors: Fadel M A , Metwally M A , Elmayyah W M , Elsherif I A
Published: October 2019

The fuel and air flow rates are the main parameters affecting the gas turbine engine performance. The burned fuel in the combustor is the main source of heat energy. The fuel metering system (FMS) provide these engines with precise fuel mass flow rates required for regulation process. One of the most important and challenging concerns of engine design and control is, driving a valid model for the FMS. Physics-based models require well identification of the electrical and hydraulic system parameters. Measuring these parameters for the system under study, like the internal dimensions of these system components is very hard because of the system complicity and integrity. In this case it is preferred to treat the system as a black box. In this paper a transfer function model for an electrohydraulic FMS has been estimated and validated using MATLAB system identification toolbox (SIT). FMS closed loop measurements have been done for data set preparation process. Linear Variable Differential Transformer (LVDT) integrated in this system has been used for measuring the metering valve displacement which is proportionally represents the output mass flow rate. Linear variable differential transformer (LVDT) signal conditioning circuit has been designed and implemented to provide DC output voltage, proportional to the system output volume flow rate. Another conditioning circuit has been designed for output current amplification process required for electrical solenoid driving. The driven transfer function model has been validated using a different measured data set to insure a good representation of the physical system. Results show that the obtained model follows the real system with good accuracy and demonstrate the effectiveness of the transfer function modelling for the FMS.
Influence of exit configuration on the flow fields and oscillation characteristics inside and outside the fluidic oscillator
Authors: Abdulnaim Ahmed M , Emara Ahmed A , Moneib Hany A
Published: October 2019

The fluidic oscillator shows very promising outcomes as an actuator in active flow control applications as it features several characteristics including no-moving parts, self-excitation, rigidity and reliability. The fluidic oscillator can be utilized in diverse applications including active-control of combustion and flow separation. The present work investigates the exit configuration influence on the flow dynamics of a small-scale double-feedback fluidic oscillator. Three configurations were modelled to examine the effects of the inclusion of a splitter inside the exit channel as well as the whole elimination of both the exit channel and splitter. Experimental results were obtained using particle image velocimetry (PIV) laser system with water as a working fluid and time-resolved pressure measurements using a hydrophone. Two-dimensional computational models based on Unsteady Reynolds-averaged Navier-Stokes (URANS) equations and shear stress transport (SST) were utilized considering the flow to be turbulent, incompressible, and isothermal. The results indicate that the exit configuration has no significant effects on the frequencies, while the jet deflection angle of the outflowing jet increases and the jet tends to be continuous when the splitter is removed. The splitter increases the outflow fluctuation amplitudes which would be suitable for diverse applications.
Controller parameter tuning using actor-critic algorithm
Authors: Ahmed Ayman Elshabrawy M
Published: October 2019

In this paper a new reinforcement learning strategy is used for on-line tuning the control system of the aerodynamic missile. Aerodynamics missile automatic control system’s mission is to overcome the missile’s flight various disturbances encountered in the process of precise and real-time control of missiles attitude. Reinforcement learning algorithm (RL) is used to tune a PID controller to replace “gain schedule” Technique usually used. The result shows that RL with the new reward function is able to optimize the PID parameters with advantage over old method in terms of convergence speed and smaller overshoot.
Control of master slave robotics system using optimal control schemes
Authors: Rashad Sara A , Sallam Mohamed , Bassiuny A M , Abdel Ghany A M
Published: October 2019

This paper presents application of Proportional Integral Derivative (PID) and Non-linear PID (NPID) controllers to optimally operate the master slave robotic system. Teleoperation is widely used in different applications, such as surgical robots, underwater vehicles, power lines and even in space. However there are problems in teleoperation systems that may lead to degradation in system performance or even to system instability. This paper presents new and optimal control schemes that can satisfy the required performance, insure system stability and achieve zero tracking error in presence of constant time delay and model approximation. Optimal gains are obtained using the Genetic Algorithm in a systematic way that could be applied to other control schemes. The results proved the effectiveness of both control schemes than the previously applied scheme. The NPID control scheme has better performance, provided position tracking and achieved zero tracking error in less settling time than PID one. The results obtained by the presented control schemes are evaluated based on comparing the system performance using three different types of controllers which are P-like, Genetic PID and Genetic NPID. The study was carried out using MATLAB/SIMULINK 2017a.
Design and implementation of new security architecture for wireless network
Authors: Mahaba Mohammed M. , Megahed Mohammed H. , Ghalwash Atef , Rezka Mohammed Abu
Published: October 2019

Tactical Networks rely on modern communication technologies to connect soldiers and commanders engaged in the battlefield and enable enhanced information flow and data gathering, allowing for decision making based on real-time data analysis. Tactical network is a wireless communication network where wireless tactical network security is a milestone because a soldier does not know from where and when the attacks come.In this paper, a dangerous attack over the deployed tactical network is proposed through group of drones which are sent to the tactical network headquarter. The drone’s mission is to identify every device MAC, IP, Name and Location to intercept data or destroy the devices. Also, in this paper, a proposed solution is given for this proposed attack through changing MAC, IP, Name and Location for every device in the headquarter periodically according to the attack time and the devices importance. The MAC, IP, Name and Location must be changed before the drones return to enemy territories.A software program is developed to change MAC, IP, and Name periodically from centered server with no conflicts. The performance analysis for the proposed solution have been taken into consideration the metrics of packets drops, time delay, communication overhead and storage overhead during the changing time. A software tool verifies the changing of IP, MAC and Name for every device. This solution ensures that before the drones return to enemy territories all devices fixed parameters of MAC, IP, and Name are changed.
Design and implementation of LTE wide band coupler
Authors: Allam A. M. M. A. , Abo Sree Mohamed Fathy , Ibrahim Muhammad Aly
Published: October 2019

The article is devoted to design, analysis and implementation of directional coupler for LTE wide band application. It is implemented on FR4 with substrate thickness 1.6 mm, loss tangent of 0.025 and relative permittivity 4.3. It has a coupling coefficient -20db at 2.4 GHz frequency. It is designed using CST microwave studio tool. Conventional and metamaterial ones are illustrated. The later one enhances the scattering parameter of the coupler. The isolation is improved from -27db to -36db.
Chaos modulation in semiconductor laser with optoelectronic feedback
Authors: Ibrahim Raghad I , Al Naimee Kais A M , Yaseen Sameer Kh
Published: October 2019

The experimental and numerical study of chaos modulation will be presented in two stats, first, when the frequency of the external perturbation is varied, secondly, when the amplitude of this perturbation is changed. The dynamics of the laser output are analyzed by Fast Fourier Transformation, attractors and bifurcation Diagram. Some frequencies could be hidden other appeared, when the frequencies are hidden, the communication link considered as secure.
Vaporization-controlled simplified model for liquid propellant rocket engine combustion chamber design
Authors: Belal H , Makled Ah El-S , Al-Sanabawy M A
Published: October 2019

The design of liquid propellant rocket engine (LPRE) is a very complicated process; this is due to two main concerns: First, the requirements to satisfy the issues of performance, stability and compatibility. Second, the complicated, interacting processes inside thrust chamber. In this paper, an attempt to illustrate the importance of different parameters affecting performance, stability and compatibility is performed, followed by extensive study of processes inside thrust chamber. The result of processes study is developing the concept of “rate limiting process” which means that the process that can be considered the most important hence the design can be done mainly by considering it alone. This is done by developing a 1D vaporization-controlled model with its application to two case studies to illustrate model validation and application. It was found that the 1D model is valid as long as the vaporization process is the slowest process in this case the error in computing chamber cylindrical length is ∼15%. However, if the mixing process is slow, or the reaction process in gas phase is slow as in the second case study of RFNA/Tonka250 case, the error grow and may reaches 50%
Optimized planar terahertz Yagi-Uda antenna using hybrid GSA-PSO optimization algorithm
Authors: Megahed A , Mahmoud K R , Shaker A
Published: October 2019

In this paper, a planar Yagi-Uda antenna design for Terahertz applications is presented and optimized. The lengths of Yagi-Uda antenna elements beside the spaces between directors’ elements are optimized seeking for obtaining high gain and minimum return loss simultaneously at 300 GHz. Thus, the directivity enhancement enables to overcome the high atmospheric attenuation influence that faces the high frequency range and limit its communication capabilities, and the return loss minimization enables to minimize the return loss to improve the impedance matching besides, reducing the mismatching losses. The Gravitational Search Optimization Algorithm with Particle Swarm Optimization algorithm (GSA-PSO) as a hybrid technique is applied on the antenna elements using an offline link between MATLAB program and Ansoft HFSS simulation program. To show the convergence capability of the GSA-PSO, the results are compared with those obtained by other algorithms such as gradient local algorithm and genetic global algorithm (GA). The optimized antenna showed high gain of 15.84 dB with a return loss of -45.27 dB compared to 15.4 dB and -15.6 dB for the conventional counterpart design, and with gain of 15.8 dB, and return loss of -21 dB for the genetic algorithm, and finally with 15.75 dB, and -28 dB for the gradient algorithm. Furthermore, the GSA-PSO algorithm improves the search capability by 30%, compared with the GA algorithm.
Enhancing the performance of CNN-based blind image steganalysis approach using multi-GPU TESLA P100
Authors: Mustafa Eslam M , Elshafey Mohamed A , Fouad Mohamed M
Published: October 2019

Blind image Steganalysis is the binomial classification problem of determining if an image contains hidden data or not. Classification problems have two main steps: i) feature extraction step and ii) classification step. Traditional blind image steganalysis approaches use handcrafted filters for the first step and use classifiers such as support vector machine (SVM) for the second step. The rapid development of steganographic techniques makes it harder to design new effective handcrafted filters, which negatively affect the feature extraction step. Recently, Convolutional Neural networks (CNNs) are introduced as an auspicious solution for this problem. CNN-based steganalysis can automatically extract features from the input images without using handcrafted filters. Although considerable success has been achieved with CNNs, CNN-based applications are considered as time consuming applications. Accordingly, it is important to quicken the CNN-based steganalysis approaches training in order to make them more applicable. This paper suggested an implementation technique of the improved Gaussian-Neuron CNN (IGNCNN) steganalysis approach on GPUs. In this paper data parallelism concept is applied to the convolutional layers while model parallelism concept is applied to the fully connected layers. Results show that the proposed method provides better performance as compared with IGNCNN [1] by an average speed up factor of 1.4 X.
A Novel Robust Adaptive and Compound Control of an Adaptive Neural Network, SMC and PI for Manipulators
Authors: Vu Duc Ha , Huang Shoudao , Tran Thi Diep
Published: October 2019

In this paper, a new compound control scheme is proposed for manipulator based on radial basis function neural network (RBFNNs), sliding mode controller (SMC) and proportional–integral (PI) controller. In this control scheme, the filtered tracking error is the input of the RBFNNs update laws, SMC, and PI controller. The RBFNNs uses three-layer to approximate uncertain nonlinear manipulator dynamics. A robust sliding function is selected as a second controller to guarantee the stability and robustness under various environments. By using additional PI controllers, the goal of manipulator tuning is to minimize chattering signal, tracking performance, and overshoot can be realized. Simulation results highlight performance of the controller to compensate the approximate errors and its simpleness in the adaptive parameter tuning process. To be concluded, the controller is suitable for robust adaptive control and can be used as supplementary of traditional neural network (NN) controllers.
Research on Mechanism of Film Pressure Loss in Water-lubricated Bearing
Authors: Lun Wang , Nan Wang , Yubo DU , Litao Yang , Peng Wang , Xiaokui Yue
Published: October 2019

Due to the low viscosity of water, the water film is not easy to form, and the water-lubricated bearing system has the characteristics of airtightness. Therefore, it is difficult to obtain an accurate water film pressure distribution through experiments. Aiming at the loss of water film pressure in the process of water film pressure transmission caused by L-type pipeline in the existing wireless sensor testing methods for water film pressure, a mathematical model of water-lubricated bearing system pipeline pressure loss is established by numerical analysis method, and the corresponding physical model is established by using ANSYS software. The mechanism of pressure loss is studied by simulation. Finally, the test results were corrected and analyzed. The results show that the higher the flow rate of lubricating water at the inlet of the pipeline, the greater the pressure loss of the water film; the higher the shaft speed, the greater the local pressure loss; the longer the pipeline, the greater the pressure loss of the straight pipe section of the L-shaped pipeline, and the dynamic condition of the pipeline The pressure loss and energy loss are much more severe than static conditions.
Hydraulic control system of mechanical energy stored type powder high velocity compaction machine
Authors: You Dongdong , Zhu Qian , Zhu Yanghui , Li Fenglei
Published: October 2019

An automatic control scheme of spring energy storage by hydraulic control of spring compression is presented and implemented in this paper to improve the automation level, control accuracy and production efficiency of the existing HVC machine with mechanical energy storage type. The hydraulic system, servo system, and PLC codes are developed. The PID control optimization is applied for the control error accuracy of the machine. The transfer function is derived, and the genetic algorithm is used to optimize the PID parameters. The control scheme is implemented in the updated machine. The experimental results of iron powder HVC are in agreement with the predicted and calculated values. The reliability and validity of the automatic control scheme is verified. The research facilitates the industrial application of this kind of equipment.
A study on decompresses heat pump dryer for drying of shiitake mushrooms at medium temperature
Authors: Goh Y J , Kim Y H , Lee B , Jung H C , Lee S R , Kim K M
Published: October 2019

This study developed a drying method and a dryer that are optimized for shiitake mushrooms. They are mainly being cultivated and consumed as food and medicine in Korea, Japan, China, and Southeast Asia. They generally contain lots of moisture. For this reason, the use of a dryer causes problems such as decomposition and spoilage, and natural dry processing is preferred. To resolve these problems, various drying methods have been proposed (e.g. hot air drying, heat pump vacuum drying) but there has been a difficulty in maintaining a medium-temperature range of 30 to 40°C, the optimal temperature environments for retaining their main components. The study developed a 2-stage decompresses resistive heat pump dryer that can operate also in medium-temperature environments - existing decompresses heat pump dryers have been able to operate only in high-temperature environments. A dryer optimized for shiitake mushrooms that are being produced and distributed in large quantities was proposed, and the utility of the machine was proved through experiments.