bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of pump intensity on atomic spin relaxation in a vapor cell*
Authors: Yang Chen , Zuo Guan-Hua , Tian Zhuang-Zhuang , Zhang Yu-Chi , Zhang Tian-Cai
Published: October 2019

Atomic spin relaxation in a vapor cell, which can be characterized by the magnetic resonance linewidth (MRL), is an important parameter that eventually determines the sensitivity of an atomic magnetometer. In this paper, we have extensively studied how the pump intensity affects the spin relaxation. The experiment is performed with a cesium vapor cell, and the influence of the pump intensity on MRL is measured at room temperature at zero-field resonance. A simple model with five atomic levels of a Λ-like configuration is discussed theoretically, which can be used to represent the experimental process approximately, and the experimental results can be explained to some extent. Both the experimental and the theoretical results show a nonlinear broadening of the MRL when the pump intensity is increasing. The work helps to understand the mechanism of pump induced atomic spin relaxation in the atomic magnetometers.
Improvement of 2.79-μm laser performance on laser diode side-pumped GYSGG/Er,Pr:GYSGG bonding rod with concave end-faces*
Authors: Zhao Xu-Yao , Sun Dun-Lu , Luo Jian-Qiao , Zhang Hui-Li , Fang Zhong-Qing , Quan Cong , Hu Lun-Zhen , Han Zhi-Yuan , Cheng Mao-Jie , Yin Shao-Tang
Published: October 2019

A comparative study on the laser performance between bonding and non-bonding Er,Pr:GYSGG rods side-pumped by 970-nm laser diodes (LDs) is conducted for the thermal lensing compensation. The analyses of the thermal distribution and thermal focal length show that the bonding rod possesses a high cooling efficiency and weak thermal lensing effect compared with the conventional Er,Pr:GYSGG rod. Moreover, the laser characteristics of maximum output power, slope efficiency, and laser beam quality of the bonding rod with concave end-faces operated at 2.79 μm are improved under the high-repetition-rate operation. A maximum output power of 13.96 W is achieved at 150-Hz and 200-μs pulse width, corresponding to a slope efficiency of 17.7% and an electrical-to-optical efficiency of 12.9%. All results suggest that the combination of thermal bonding and concave end-face is a suitable structure for thermal lensing compensation.
Conservation laws and stability of higher derivative extended Chern-Simons
Authors: Abakumova V A , Kaparulin D S , Lyakhovich S L
Published: October 2019

The higher derivative field theories are notorious for the stability problems both at classical and quantum level. Classical instability is connected with unboundedness of the canonical energy, while the unbounded energy spectrum leads to the quantum instability. For a wide class of higher derivative theories, including the extended Chern-Simons, other bounded conserved quantities which provide the stability can exist. The most general gauge invariant extended Chern-Simons theory of arbitrary finite order n admits (n − 1)-parameter series of conserved energy-momentum tensors. If the 00-component of the most general representative of this series is bounded, the theory is stable. The stability condition requires from the free extended Chern-Simons theory to describe the unitary reducible representation of the Poincaré group. The unstable theory corresponds to nonunitary representation.
Geometrical model of massive spinning particle in four-dimensional Minkowski space
Authors: Kaparulin D S , Lyakhovich S L , Retuncev I A
Published: October 2019

We propose the model of a massive spinning particle traveling in four-dimensional Minkowski space. The equations of motion of the particle are obtained from the requirement that its classical paths lie on a cylinder with the time-like axis in Minkowski space. All the paths on one and the same cylinder are gauge equivalent. The equations of motion are found in implicit form for general time-like paths, and they are non-Lagrangian. The explicit equations of motion are derived for trajectories with small curvature and helices. The momentum and total angular momentum are expressed in terms of characteristics of the path in all the cases. The constructed model of the spinning particle has a geometrical character, with no additional variables in the space of spin states being introduced.
Analysis, and machine learning anomaly detection of the VELO-LHCb calibration
Authors: Majewski Maciej
Published: October 2019

Silicon detectors are an extraordinary piece of equipment that has become the cornerstone of research in modern high energy physics. They are becoming increasingly useful in medical research as well. LHCbs VELO detector is itself, a microstrip silicon vertex detector. It is the heart of LHCb spectrometer and plays a vital role in the reconstruction of particle tracks. The data gathered by VELO is used in LHCb studies of CP violation and heavy flavour physics. This work presents the studies on the calibration parameters of the VELO-LHCb. The inference from the analysis, with the use of probabilistic programming, is then used to create a machine learning based anomaly detection system in the space of VELO calibration.
Study of radiation damage and possible upgrade of the CMS ECAL Laser Monitoring system
Authors: Savchenko Y
Published: October 2019

The Electromagnetic Calorimeter (ECAL), one of the main subsystems of the CMS detector, measures the energies of electrons and photons. The ECAL consists of 75848 lead tungstate (PbWO4) crystals. The transparency of crystals is affected by irradiation, and the laser monitoring system is designed to measure the transparency changes for each ECAL crystal over time. In the future, the High-Luminosity LHC upgrade will increase the integrated luminosuty of the LHC and lead to higher radiation damage in all components of the CMS detector. In this work we report the proposed upgrade for the laser monitoring system and the results of computing crystal transparencies based on Run 2 data.
The microscopic black hole production at the LHC with the CMS experiment
Authors: Seitova D , Savina M V , Shmatov S V
Published: October 2019

CMS (Compact Muon Solenoid) is one of the two general-purpose detectors at the LHC. The physics programme of the experiment ranges from checking the Standard Model to searching for a new physics. One of the most interesting directions in the new physics is the extra dimensions. In modern theoretical ideas related to the concept of extra dimensions and multidimensional low-energy gravity, one can expect to observe the creation of the microscopic black holes at the LHC in proton-proton collisions at currently available energies.
Contribution of Space Factors to Decisions on Comfort of Healthy Building Design
Authors: Zhen Qi , Huang Qiong , Zhang Qi
Published: October 2019

Healthy buildings are closely related to human health and comfort. Based on the literature survey, this paper explores the definition of comfort in healthy buildings. Through literature analysis and expert interviews, 16 building space factors affecting building indoor environment were identified. To introduce the building space factors into the research on the comfort evaluation of healthy buildings, 152 questionnaires were sent out and the relationship between these factors and building indoor environment comfort evaluation and their rankings were discussed. Data analysis includes the reliability analysis, normal distribution test, Pearson correlation coefficient and MANOVA. The results have shown that the perceived comfort is strongly influenced by the building space factors, and the relationship is complicated. The rankings from professionals and non-professionals were different. Several factors have been identified as key influencing factors. Besides, the perceived comfort is also related to other factors such as age, gender, etc. Such discovery primarily provides an ordering of building space design factors, which will contribute to the buildings’ health, comfort and sustainable development through architectural design from an architect’s perspective.
Urban Policy as a Main Key towards Sustainable Built Environment of Popular Neighbourhood: Case Study of “El Cabanyal” Valencia Spain
Authors: Mahmoud Randa A. , Wael Ahmed
Published: October 2019

El Cabanyal, a popular neighbourhood and old fishermen’s village, in the Valencian Community, eastern Spain, is a very explicit example on how popular neighbourhoods can be drastically transformed in line with urban policies’ evolution. This neighbourhood -that has a strong cultural identity expressed by its vernacular architecture, local art and social life-kept resisting gentrification during the last 30 years. As a result, this neighbourhood has shown a great deal of deterioration as a price that had to pay in order to keep its own identity within the Mediterranean city of Valencia.

This paper demonstrates the evolution of local and popular neighbourhoods according to adopted urban policies by taking the neighbourhood of El Cabanyal as a case study. Therefore, it will firstly scrutinize the proposed urban policies/strategies by the regional government in order to develop this neighbourhood. Secondly, it will shed light on the participatory design solutions based on the local community involvement, to develop the area without destruction and getting use of its potentials. Finally, it will propose a diagnostic tool and ecological urban solutions that can be elaborated in order to tackle such complex problems.

We believe that the change of urban policies can give different spectrums to sustainable development strategies by addressing social problems and heritage conservation questions. The delicacy of the issue is a typical 21st Century problem encountering different contexts. It can be an obstacle for sustainable urban/social development if not addressed correctly. This is why it must be integrated in the strategies proposed by urban policies’ decision makers.
Energy and Environmental performance of a green certified office building in the hot dry climate of India
Authors: Gupta Rajat , Gregg Matt , Panchal Rupesh
Published: October 2019

This paper applies a customised post-occupancy building performance evaluation (BPE) approach to evaluate the actual performance of a Platinum-certified green office building in the extreme hot dry climate of India from both technical and occupants’ perspectives. The in-use energy and environmental performance of the office building was examined using energy data on consumption and generation, monitoring of environmental conditions (temperature, relative humidity, CO2), along with occupant satisfaction survey. Total annual energy use of the building was measured as 100 kWh/m2/year with photovoltaic generation contributing 18kWh/m2/year. Although total annual energy use was found to be 42% less than the typical office benchmark, about 6% more energy was used than predicted. Indoor air quality was perceived to still but fresh and neither too dry nor too humid. Despite this, some spaces had relative humidity measurement over 70% for more than 50% of occupied hours. Daylight factor was consistently below 2% in many areas due to internal partitions; however, BUS survey (105 responses) results showed that 71% of occupants were satisfied with lighting quality, overall comfort and other variables. Such differences between measured and perceived indoor environment indicate the role of occupant adaptation in building performance.
Study of the Uncertainties Influencing the Energy Performance Assessments of Two Very Different Urban Houses in Wallonia
Authors: Monfils S , Hauglustaine J-M
Published: October 2019

Implemented by the European EPB directives, the Energy Performance Certification has been designed by authorities to “provide clear information about the energy performance of a building”. Studies led in Wallonia show however that official results are often too distant from reality and difficult to understand for the lay person. This paper focuses on the comparison between two certified old urban brick single-family houses in the Walloon residential stock: a highly efficiently renovated “exemplary building”, described in detail, versus an inefficient and poorly described second house. After presentation of the case studies, this paper will investigate the uncertainties that surround the description of the “energy systems” and the standardized calculation method. This research explores the possibilities of elevating the confidence in the certification results by adding information on the description of the envelope and systems, by re-integrating the human factor in the equations (through a questionnaire collecting by interview the dwellers’ energy-related behaviours and practices), and by using dynamic simulations. The comparison of the results to the official standardised results indicates that additional data on the household’s composition, practices and energy-related behaviours are as much needed as a more accurate description of the energy system, which is penalized by default values and a severe standardisation of the calculation method.
Comparison between environmentally designed houses and standard houses regarding thermal behavior
Authors: Nessim M , Abdin T , Mostafa Z
Published: October 2019

Based on the literature review and environmental studies, it is well known that the fundamental design standards focus on the building orientation, materials, form, window wall ratio, and passive tools for cooling in hot climates. This was the reason behind this paper, to verify and prove that if a building is designed according to these standards then it could achieve thermal comfort and energy efficiency. So, a comparison was held between four case studies, two of them were designed according to those standards and the other two were not. Hygrometer data loggers that measure ambient air temperature and relative humidity were placed in living rooms and on roofs in the four villas for one month in order to compare and analyse the measurements. In the coming paragraphs, each case study is explained and measurements and analysis are presented in order to reach the conclusion of this paper study. Fixed parameters were set for comparison between the four cases, those parameters were as follows: Orientation- wall thickness- building material- WWR (window wall ratio) - Number of Floors- Type of roof – Surroundings. Data was collected based on these parameters to be able to compare between the results. After comparing those parameters in the four villas, it was concluded the great influence of the surrounding buildings on each villa on its internal temperature. And so therefore a simulation has been made to measure the effect of the surrounding buildings.
Seasonal thermal adaptability of shopping arcades in hot and dry climates. The case of Nicosia’s historic centre
Authors: Malaktou E , Philokyprou M
Published: October 2019

‘Traditional’ semi-open retail environments have recently received increasing scientific attention due to their ‘rediscovery’ as passive and low-energy architectural elements, which could promote sustainability in the urban realm. This is of particular importance when considering that fully-closed contemporary shopping centres constitute high-energy consuming spaces during the cooling period, in hot climates. The present study deals with the thermal behaviour of shopping arcades, a ‘traditional’ bioclimatic urban feature, in the hot and dry climate of Cyprus, by means of on-site air temperature recordings. The aim of this research is the bi-seasonal thermal performance assessment of this semi-open space, so as to inform energy retrofitting practices and promote bioclimatism in contemporary designs. The research shows that arcades were designed mainly to address the hot climatic conditions of the island. The sample tested achieved a significant daytime cool island up to 4.4K, during the cooling period. The best performance was achieved in arcades which presented minimum openings to envelope areas. In contrast, a daytime air temperature reduction which reached 2.1K, was observed in arcades during the heating period, indicating a negative thermal effect. Overall, the positive thermal contribution of arcades during the cooling period proved stronger than the negative thermal effect during the heating period.
The Intuitive Bioclimatism and Embedded Sustainability of Cypriot Vernacular Farmhouses, as Principles for their Strategic Restoration and Reuse
Authors: Sivitanidou A , Nikolopoulou M
Published: October 2019

This research aims to investigate the bioclimatic design, sustainability and environmental behaviour of Cypriot vernacular farmhouses, as part of small-scale family-owned farmsteads. These farmhouses, located in village outskirts, are still in operation, greatly supporting the primary sector of Cypriot economy. Current uses have conduced arbitrary modifications in their morphology, layout, construction and usage, which in the past had contributed positively to thermal comfort and household autonomy. In the present, these modifications caused farmhouses to become climatically inept, devoid of Bioclimatism and Sustainability. This research employs multiple case studies with a fully-integrated mixed-methods design. Findings are drawn via triangulation of qualitative and quantitative data from ethnographic participant observation, post-occupancy evaluation survey, interviews, in-situ documentation and environmental monitoring. Initial findings show that there is a tangible and intangible relationship between the dwelling, its inhabitants and the environment, strengthened in time due to tradition, accumulated knowledge and experience, and born out of necessity, scarcity and practicality. It is an interdependent, dynamic and adaptive reciprocity, induced by the complex interplay of socio-cultural, economic, technological, aesthetic and environmental factors. The end result was for bioclimatic design to be applied intuitively and sustainability to be embedded in the form, configuration, construction and operational modes of farmhouses. As Cyprus attempts to conform to its EU obligations regarding the sustainable development of rural environments and make the transition towards nearly-zero energy buildings, the Cypriot vernacular farmhouse can offer valuable lessons in building design and performance, whilst provide clear guidance for its strategic restoration and reuse.
Sensitivity energy analysis for the Saudi residential buildings envelope codes under future climate change scenarios: the case for the hot and humid region in Jeddah
Authors: Abuhussain M A , Chow D H C , Sharples S
Published: October 2019

The residential building sector of the Kingdom of Saudi Arabia (KSA) is the primary consumer of energy consumption, using around 50% of the total amount of electricity KSA generates. Much of this is caused by the heavy demand for air conditioning due to the extremely high temperatures in the country. On the basis of KSA’s government initiatives, it is compulsory that new residential buildings adhere to strict energy codes. This study places its focus on analysing the ability of KSA’s new residential building envelope codes to successfully function according to the climate at present and in the future. In Jeddah, KSA, two single-family villas were examined with DesignBuilder simulation software and impacts of the new codes that were applied were assessed. Achieving the validation of the energy model requires the measurement of temperature indoors and outdoors. In addition, a long-term financial study was conducted to analyse the economic feasibility of the codes under the current and future climate change periods. Although the study shows the new codes produce a reduction in energy consumption by 14% to 40 % from the current cases, with the inclusion of wall and roof insulation being the most effective features of the new requirements of the codes. However, these codes cannot nullify the effect of future climate change.
Awareness assessment of biophilic design principles application
Authors: Nasr Aly Tahoun Zeinab
Published: October 2019

The green architecture has developed in the last few years, since the sustainable system have evolved specially in buildings construction. The aim is to keep sources of non-renewable energy. With this evolution, a new concept related to the green architecture has been emerged called biophilia, or the living nature which is related to the human inheritance of loving nature. Many studies have proved that the existence of humans in the external environment reduces physiological and neurological distress and makes them feel better. This research deal with definition of architectural biophilic design with relation to the physical and physiological human health; as well as the merging of building interior with nature and their effects on the employee in terms of health and productivity. Moreover, it investigated the applications of the biophilic design inside work place to make it more comfortable and effective for the employee to enhance their productivity. The aim of this paper is to assess awareness about the biophilic design and its impact on employees and their wellbeing in Egypt because it’s too important to apply biophilic design especially at workspaces here in Egypt which had big percentage of unsuitable places to work full of stress and anxiety.
Analysing the relationship between urban form and urban heat island effect at a city-block scale
Authors: Deng Xi , Zhang Shunqian , Jones Phillip
Published: October 2019

Over the last twenty years China has witnessed rapid urbanisation process. The modification of urban land surface due to urbanisation changes not only affects the geometry of an urban settlement but also its thermal properties, which may give rise to the urban heat island (UHI) affect. Although there has been a large amount of research on mitigation strategies of UHI at the urban scale, there is still a lack of research that concerns the influence of urban geometrical settlement on UHI at a city block scale. Chengdu, a megacity in south-west China, has been chosen as the research subject in this study, to identify the existence of the UHI phenomenon, to measure its magnitude, and to investigate the relationship between UHI and urban design variables, including Floor Area Ratio, Building Coverage Ratio, Green Coverage Ratio, Building Height, Plot-layout Form, and Project Type (function). In this study, urban maps of UHI had been derived from MODIS satellite data for 103 selected projects and 28 urban zones. Correlations were carried out between UHI intensity and urban design variables. The study has developed design guidelines for improving outdoor thermal performance at an city block level. Moreover, a new approach to observe UHI at multi-scales in a long-time period had been conducted, providing a new method to analysis UHI at a city-block scale.
Regional Space Strategy and Zero-energy Engineering Strategy: An Analysis of “In-Between Nature” for Solar Decathlon China 2018
Authors: Shaosen WANG , Feng SHI , Shurui YAN , Hong CHEN
Published: October 2019

With an analysis of the project “In-Between Nature” for SDC2018 that got 3rd place in the competition, this paper explored a combined approach to achieve zero-energy consumption building: space strategy learning from local architecture prototypes which is mainly passive, and engineering strategy which covers life-cycle of the building. During the competition, statistics such as temperature, humidity, energy produced and consumed are measured, proving that this combined strategy is feasible and the house has achieved the goal of zero-energy in Dezhou during early August, when the temperature and humidity is highest of a year.
Adaptive comfort assessment for different thermal insulations for building envelope against the effects of global warming in the mid-western Brazil
Authors: Lalesca Aparecida da Guarda Emeli , Gabriel Elaise , Mansuelo Alves Domingos Renata , Cleonice Durante Luciane , Julio Apolonio Callejas Ivan , Carlos Machado Sanches João , Andrade Carvalho Rosseti Karyna de
Published: October 2019

The consequences of global warming have gained worldwide importance, also in the scope of built environment when related with the thermal comfort conditions of users. In this way, the objective of this research is to analyse the effects of global warming on the hours of thermal comfort of dwellings, with different thermal insulators in the external walls, considering the emission scenario A2 of the Fourth Assessment Report (AR4) of the IPCC. The methodological procedures consist of four stages: preparation of climate files for Future Scenarios (2020, 2050 and 2080) from the base climate file (base scenario); definition of a dwelling for study object (Tbase); preparation of thermal insulating intervention proposals, such as: EPS (T1), rock wool (T2) and glass wool (T3) and evaluation of thermal comfort conditions using the adaptive thermal comfort method. The results indicate that the air temperature increases by 21.5% and the relative air humidity reduces by 22% until the 2080 scenario if compared to the base scenario. From these new conditions, the percentages of Tbase comfort hours suffer a reduction of 63.61%, increasing the hours of heat discomfort by 98.48%, in the scenario of 2080 in relation to the base scenario. With the adoption of insulation, the T1 typology presented comfort hours of 58.4%, reducing to 17.9%. However, typologies T2 and T3 presented similar behaviour, with 27.2% of hours in comfort and 67.4% of hours in heat discomfort, in the 2080 scenario in relation to the baseline scenario. Therefore, it can be concluded that typologies T2 and T3 presented greater resilience to the effects of global warming, but it is necessary to incorporate constructive interventions to absorb the impacts of climate changes and provide better conditions of thermal comfort.
Optimization of low signature base bleed propellant formulations
Authors: Youssef Ehab M , Elshenawy Tamer , Mostafa Hosam E , Radwan Mostafa , Elbeih Ahmed
Published: October 2019

Base bleed (BB) projectile is one of the choices to minimize projectile base drag leading to 30% range extension. The secondary smoke resulting from the burning of BB is considered to be one of the drawbacks of the BB and it is an essential factor in detecting the projectile flight towards the target. Based on intensive ICT formulations results, optimization study has been carried out using design expert software to optimize the base bleed formulations that can produce minimum amount of secondary smoke with the lowest flame temperature and higher impulse. The optimized base bleed propellant formulations, that have been found, were those of 10.27 and 7.02 % for both RDX/AP and Mg/AP ratios respectively. The experimental preparation and testing of the optimized two base bleed types showed lower values of secondary smoke by 16% and 55% for RDX/AP and Mg/AP ratios respectively when tested experimentally alongside the baseline base bleed reference composition.
Performance characteristics of modified HMX-gun propellants
Authors: Elbeih Ahmed , Wafy Tamer Z. , Elshenawy Tamer , Hussein Ahmed K. , Abd-Elghany Mohamed , Hammad Sara M. , Yehia Mohamed
Published: October 2019

Nitramines explosive, HMX, was used for preparation of gun propellant formulations based on slurry technique. Acrylonitrile butadiene rubber (NBR) was used as a polymer for coating HMX crystals in addition to the traditional Nitrocellulose matrix. Ballistic performance of the compositions was evaluated on the basis of closed vessel test. Heat of combustion was also measured using a calorimetric bomb. Impact and friction sensitivities of the prepared compositions in addition to the ignition temperature were also determined. The obtained results reveal that gun propellant compositions based on approximately 50 percent HMX could provide relatively high performance and relatively suitable sensitivity for its application as gun propellant.
Factors affecting irradiation of nano & micro materials by laser treatment industrial unit
Authors: Ahmed Hebatalrahman
Published: October 2019

This work presents an industrial unit for hardening and treatment of nano-materials and micrometers to improve their physical, chemical and mechanical properties by exposing them to laser radiation. The treatment process is carried out through the laser treatment industrial unit. It is composed of circular metal base with motor, rectangular holder, moving sides. The sample installation cavities which are metal joints that widen and shrink according to sample dimensions by incorporating the cavities vertically and moving the sides, the unit has black front and back barrier to prevent lasers with bottom cavity to store the black barrier. Scaling must be compatible with laser diameter or width; the unit has partition barriers and fixing arms to control the process. Laser and unit are operated to complete the treatment, method is physical process, the laser beam go through treated material without being absorbed or interact by transparent material, the treated nanomaterials or short fibres were collected. The samples were exposed to Nd -YAG third harmonic generation and Argon ion CW laser. The hardness was measured before and after laser irradiation. The current work will present an application on the hardening of E-fibre glass 731ED 1/32″.The change in hardness were explained by raman spectroscopy. The research end with conclusions and recommendation for the expected application of the new treatment unit and method.
Process parameters optimization for producing AA6061/(Al2O3, Gr and Al2O3+Gr) surface composites by friction stir processing
Authors: EL-Eraki B R , EL-Sissi A R , Khafagi S M , Nada H S
Published: October 2019

The present study uses Al2O3, graphite and hybrid Al2O3 and graphite nanoparticles as reinforcement particles within AA 6061 to produce a surface composite metal matrix using multiple-pass FSP. The aim of this work is to investigate the effects of multi-pass FSP, type of reinforcement particles and effects of T6 post-treatments on the microstructure and mechanical properties (hardness, ultimate tensile strength, and elongation) of friction stir processed (FSPed) AA6061 alloy. The results show that; all the composites produced using alumina particles in matrix material have the highest ultimate tensile strength (213 Mpa). Increase in hardness of stir zone for FSPed samples was more pronounced with post heat treatment and essentially insignificant for variation in a number of passes. The process parameters were optimized using a Taguchi method. The most influential parameter was a type of reinforcement particles. The analysis of variance (ANOVA) used to evaluate the percentage contribution for each parameter.
Experimental verification of the parameters affecting the characteristics of mechanical and corrosion behaviour of conventional and high-speed remote scanner laser welding of stainless-steel joints
Authors: El-Aziz Ahmed. M. , Khier Mahmoud Abou El , Exner Horest
Published: October 2019

Nowadays technologies have huge assortment of welding processes are available and used in joining metals. The characteristics of the microstructures through weld zones, Scanning electron Microscope investigated the grain size before and after weld with the precipitates and the size and the extent of heat-affected zones (HAZ) will primary depend on: (1) the type of metals being joined, (2) the heat treatability of the material and welding velocity, (3) the classes of welding or joining processes used. The microstructure changes arising from welding will significantly affect the mechanical and the corrosion behaviour of the welded stainless steel. Because of lack of information which welding processes are the best method and the contradictory opinions regarding efficiency of different welding techniques. Accordingly, the present study has been undertaken to evaluate the mechanical and corrosion behaviour using different welding techniques, laser welding and conventional welding. Two welding techniques for Standard Austenitic stainless steel 1.4301(304) are presenting in this study: Case (I) gas tungsten arc welding (GTAW) or TIG; Case (II) High-speed remote scanner laser-welding.
Satellite battery sensor values prediction using Bayesian ridge regression models
Authors: Galal Mohamed A , Hussein Wessam M , Abdelkawy Ezz El-din
Published: October 2019

Proper mission control plays a key role in the lifetime of space mission operation, as it ensures that all resources are efficiently utilized when achieving mission goals. Ground control station operation mainly depends on received telemetry together with models simulating spacecraft`s subsystems. Created models help in raising the level of autonomy of MCC (Mission Control Center). Data driven models describe the actual state of the subsystem in real operation situations rather than theoretical costly physical models. This paper proposes data driven models for satellite battery subsystem based on Bayesian ridge regression algorithm. The ridge coefficients minimize a penalized residual sum of squares Thirty models of all thirty battery variables (capacitance, voltage, pressure and temperature) are built from normal operation data. Sensor reading value can be predicted from an observation of all other 29 values. Faults present in sensors or in system can be detected if predicted values are not equal to actual downloaded data from satellite. Bayesian ridge regression models are validated in terms of slope, intercept, R2-value, Q2 -value P-value and standard error.
Modeling of fixed wing UAV and design of multivariable flight controller using PID tuned by local optimal control
Authors: Mobarez Eslam Nabil , Sarhan Amr , Mahmoud Mohamed Ashry
Published: October 2019

Ultrastick-25e is an unmanned air vehicle fabricated by University of Minnesota. The traditional PI control was purposed for Ultrastick-25e in both longitudinal and lateral branches. Throughout this paper, PI and PID controllers are purposed for Ultrastick-25e in both longitudinal and lateral branches of linear and nonlinear model. Two tuning methods are utilized to enhance the autopilot response of Ultrastic-25e UAV. The autopilot system robustness is tested by measuring the capability of the controllers in rejecting the wind disturbances, and attenuating the noises generated from the sensors. The genetic algorithm optimizer is utilized as the first method for tuning the PI and PID controllers and enhance the performance and robustness of the system. The Local Optimal Control (LOC) is utilized as the second method for tuning the PI and PID after that. The essential contribution of this paper is utilizing local optimal control for tuning parameters of PI and PID on UAVs for the first time. The comparative study of the results assure the superiority of this tuning method over the other tuning methods used.
Review of challenges of the design of rocket motor case structures
Authors: Hossam I , Saleh Sh , Kamel H
Published: October 2019

This paper presents the state of the art and challenges in the design of rocket motor case structures RMCS it briefly describes the construction of RMCS then lists the different operational loads that govern its design. This is followed by a review of the different materials that are suitable for use. The inherent complexities of the design process using conventional and composite materials are discussed in details; the optimum design of RMCS is studied and summarized. Finally useful conclusions are summarized to serve as a guide to the researchers and designers in this field.
Assessment of AA7075/SiO2 surface composites fabricated by friction stir processing (FSP)
Authors: Abd El-Aziz M. H. , El-Shabasy A.B. , Ahmed M. M. Z. , Hassan H. A.
Published: October 2019

Friction stir processing (FSP) was developed based on the same principles of friction stir welding (FSW) mainly to enhance the surface properties of various materials and to produce surface composites. In this work surface composites of AA7075 as the metal matrix that reinforced with ultra-fine sized SiO2 particles were developed using FSP. A groove of 3 mm depth and 1.2 mm width was made on the surface of AA7075 to provide the highest reinforcement volume fraction on the produced surface composites. FSP tool with a square profiled tool pin of 3.5 mm pin length and of 5mm pin side was used. The FSP parameters used were 600 rpm and 50 mm/min. The developed surface composites were evaluated using different metallographic techniques to investigate the macro and micro features. Also the hardness profile was measured across the processed zone. The surface composites achieved by three consecutive passes of processing showed uniform particle distribution across the stirring zone of the surface composite. Moreover, the surface composite hardness was improved by 10-30% compared to the unreinforced alloy. The tool with a square profiled tool pin enables obtaining sound surface without any visible defects.
Ultra-wide band microstrip antenna for 4G applications
Authors: Abo sree Mohamed Fathy , Ibrahim Muhammad Aly , Swelam W. , Abd El-Azeem Mohamed H. , Hennawy Hadia El
Published: October 2019

Presently, there is an expanded activity for ultra-wideband (UWB) technology for use in a few present and future applications. UWB got an exceptional attention, particularly after the approval of utilizing the unlicensed band beginning from 3.1 to 10.6 GHz for commercial use. A compact ultra-wide band microstrip antenna is introduced in this paper. The antenna consists of dual elements each having a size of 24×24 mm∧2, while the total size is 58×24 mm2. A decoupling circuit is added to the design; afterwards the spacing between the elements is adjusted. The first element covers the range between 3.29 and 6.9 GHZ using the digital ground and the second antenna covers the frequency range from 8.76 GHz to 13.27 GHz using defective ground..This type of antenna is designed to be used for 4G applications. The antenna’s structure and the parametric study, including the reflection coefficients, gain, coupling and decoupling, will be discussed further in this work. In addition to that comparison of similar UWB antennas is done.
Soft sectored fractional frequency reuse in LTE-advanced networks
Authors: AbdelNaby Eman , Ali Ihab A. , El – Haleem Ahmed M.Abd , Hamed Hesham F. A.
Published: October 2019

Fractional Frequency Reuse (FFR) has been suggested as an Inter Cell Interference Coordination (ICIC) technique in Orthogonal Frequency Division Multiple Access (OFDMA), where the cell is separated into internal and external regions. The inner means that it is close to eNB, while the outer indicates closeness to the boundaries of the cell. The main idea of FFR is to divide the cell’s bandwidth into partitions for reducing the cell interference from both inner users and the adjacent cells. The FFR has three main types including Strict FFR, Soft FFR and Sectored FFR (SFFR). This work proposes a hybrid Soft Sectored Fractional Frequency Reuse (SSFFR), which analyzes the uplink worst case Signal to Interference power Ratio (SIR). In addition, the effect of power control exponent, path loss exponent and inner radius are studied, and SSFFR is compared with SFFR. Simulation results show that, the higher SIR achieved by outer-SSFFR, enables to enhance the cell edge transmission through interference management.
Performance, mechanical and thermal properties of double base rocket propellant including copper oxide as burning rate modifier
Authors: Abdel-Ghani Nour , Elbeih Ahmed , Helal Farag , Hammad Sara M.
Published: October 2019

In this work, different percentages of Copper oxide have been added to double base rocket propellant (DBRP) as burning rate modifier. A conventional DBRP has been prepared and studied for comparison. The mechanical properties at different temperatures were studied. The heat of combustion and ignition temperature of the samples were measured. The performance represented by the operating pressure and the burning rate were evaluated at 8mm throat diameters. The thermal behavior of the traditional DBRP in comparison with a selected composition containing copper oxide was discussed. It was concluded that the addition of copper oxide in DBRP has positive effect on the mechanical properties of the traditional DBRP while slight increase in the performance properties was observed.
Analytical and numerical studies of mass flux dispersed from tapered swirl atomizer with various nozzle cut profiles
Authors: Kayed Hatem
Published: October 2019

Spraying dispersed fluid by swirl atomizer into a main gas stream in order to obtain homogeneous blended flow within a restricted distance from the atomizer position is a significant issue. The dispersal of sprayed fluid mass-flux from the atomizer should be correlated to mass flux distribution of the main flow gas. Consequently, it is essential to control the distribution of liquid mass flux from the injector to match the distribution of main gas flux to attain perfect mixing with identical liquid/gas mass flux ratio all over the pipe. The present study examines the liquid mass flux pattern injected from tapered swirl atomizer having various cut shapes. A mathematical approach to circumferentially evaluate the outlet mass fraction distribution from generalized tapered nozzle cut was analyzed. The derived mass fraction distribution equation is dependent on the flow-angle, the cut-angle, and the arc-angle. A CFD simulation was performed to evaluate the flow angle at the outlet from the nozzle cut. The finding of the present work delivers a guide for researchers and engineers to the preferred injector cut profile to give the best mass flux uniformity. The simulated spray pattern relied on circumferential mass flux at nozzle outlet has been in great coincidence with what depicted by imaging. More studies could be performed to have the most appropriate cut shape of the injector with various flow profiles of the main gas stream.
Simulator design for low pressure plasma discharges in planar geometry
Authors: Radwan S , Saleh H , Bourham M
Published: October 2019

A design of a simulator code to determine the plasma characteristics in planar geometry discharges is presented. The experimentally obtained parameters are compared to the code predictions. The experimental plasma discharge characteristics were carried out using 99.99% nitrogen as the working gas at typical pressure values in the range 0.1–0.6 Torr. The simulator code was used to obtain the discharge current-voltage, showing compatibility with experimental values. The minimum breakdown voltage at the minimum gas pressure was also obtained. The relation between the discharge current at different anode-cathode distances was also determined.
Feature extraction from high resolution satellite images using K-means and colour threshold approach
Authors: ELsharkawy Ahmed S , Abdalla Mahmoud
Published: October 2019

In recent year developments in satellite sensors tend to the availability of high spatial and spectral resolution images. The motivation of this research paper is to obtain maximum benefits of different bands from high resolution satellite images in order to put into practice an image processing algorithm solution for extraction and classification of land cover and manmade objects can be used by non-professionals. In this research paper a novel approach for image classification is presented by applying k-means algorithm and colour threshold approach onto high resolution World View 2 (WV2) image. K-means algorithm is applied on a reflectance image to extract land cover classes and manmade objects based on a colour-based segmentation method. The proposed technique is applied through MATLAB environment. The user is asked to select few points of the desired classes and the algorithm do the rest and produce vector layers of the selected classes. The experimental results prove the effectiveness of our framework to enhance the quality of classification in aspects of computational time and precision. The preliminary results are considered promising.
Modeling and control of unstable mechanical systems using control moment gyro (CMG)
Authors: El-Aal A A , Roustom M , Hegaze M M , Ibrahim M
Published: October 2019

Stabilizing of statically unstable systems such as monorail trains and the Two-wheel bike is a wide area for research. In this work bike has been used as an unstable mechanical system. Control Moment Gyro (CMG) has been utilized as a control tool to a achieve stability of the proposed system. The proposed gyroscopic system consists of single degree of freedom gimbal and flywheel placed horizontally inside the bike frame. The gimbal angular velocity controlled by DC servo motor lay on a new control approach “Linear Quadratic Regulator Plus Integral Action (LQR+I) “. Matlab model was developed for the system using mathematical equations derived from nonlinear dynamics by using Lagrange’s method to obtain simulated system response and behaviour. Proportional Integral Derivative (PID) controller has been applied to simulated model and actual test rig to ensure the simulation validity, the study compares the three techniques of control (PID,LQR and LQR+I) in terms of settling time, overshoot and steady state error. “The simulation results are illustrated with the help of graphs and tables which significantly show superior performance and robustness of LQR + I over PID and LQR.
Intelligent feedback stabilization of MIMO systems based on additively decomposable property
Authors: Elkhatib Mohamed M.
Published: October 2019

Recently, stability of nonlinear multi-input, multi-output (MIMO) system has attracted a significant number of researchers specially, due to the large development in practical implementation of nonlinear system with uncertainty. In this paper, using additively decomposable property based on the structure of a LUR’E problem, an intelligent Takagi-Sugeno fuzzy block is added in the system feedback. The new proposed system includes all the system nonlinearities as result it grantees system absolute stability. A simulation result of the new algorithm for MIMO system is introduced.
Novel functionalization treatment of MWCNTs for unmanned aerial vehicle structure
Authors: Alawy Alaa , Abdlghany Mohamed , Wafy Tamer , Hassan Ahmed
Published: October 2019

Present typescript encompasses the influences of functionalization on the carbon nanotubes (CNTs) using acid oxidation which has been widely reported not only as a purification process but also as functionalization process because it is an effect on the outer surface on CNTs. Therefore, using strong acid effect and high power sonication in addition to the nature of the acid mixture (H2SO4/HNO3) with CNTs confirm that adequate volume of carboxyl groups decorate the outer surface, this functionalization process improve the dispersibility of the CNT in the response of the final dimension of the CNTs. Because of using a high temperature for a long time more than 6 hours.

This work interested in the aspect ratio (L/D) and the final shape of the tubes by using a mild temperature process 50°C with concentration acid for not long time 5 hours, in an attempt to make experimental condition which guarantees good functionalization of the surface of MWNTs with minimizing the CNTs damage, The results were confirmed by Thermogravimetry Analysis (TGA), Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis.

In addition to the functionalization process we try to save the loss in the weight during the filtration step, in addition to decrease the time during filtration of the materials after sonication. Where the results show that actually functionalization has been done with an adequate amount at this condition, and the dilution for 2 days before filtration have been approved to be easier and faster than direct filtration after treatment.