Search results

Relating development control regulations to urban morphology analysis concepts is essential to deal with incremental change in existing contexts, relating urban morphology analysis to intangible factors of change such as land economics, human needs, politics and ideologies, helps protecting character and value of contexts from unguided change controlled by waves of political decisions, change of densities and land values. The first part of the paper discusses different approaches to urban morphology analysis, the need to development control regulations to protect character and value, the incremental nature of urban change, and urban morphology's non physical aspects effect on urban change. The second part of the paper reviews two case studies in France and Egypt to assess development control regulations in each case, how it affected urban change and area character, and examines whether urban morphology analysis was part of Development control regulations or not. It concludes with the evaluation of the second case, and the development of a frame work linking non physical factors affecting incremental change with morphological studies, showing the need to relate development control regulations to morphological analysis of town's form and non physical variables affecting form change to guide positively incremental change.

This paper aims to distinguish the relationship between the morphology characteristics of different scales and the contact performance of the mating surfaces. Also, an integrated method of the spectrum analysis and the wavelet transform is used to separate the morphology characteristics of the actual machined parts.

First, a three-dimensional (3D) surface profilometer is used to obtain the surface morphology data of the actual machined parts. Second, the morphology characteristics of different scales are realized by the wavelet analysis and the power spectral density. Third, the reverse modeling engineering is used to construct the 3D contact models for the macroscopic characteristics. Finally, the finite element method is used to analyze the contact stiffness and the contact area of the 3D contact model.

The contact area and the nominal contact pressure Pn have a nonlinear relationship in the whole compression process for the 3D contact model. The percentage of the total contact area of the macro-scale mating surface is about 70 per cent when the contact pressure Pn is in the range of 0-100 MPa, and the elastic contact area accounts for the vast majority. Meanwhile, when the contact pressure Pn is less than 10MPa, the influence factor (the relative error of contact stiffness) is larger than 50 per cent, so the surface macro-scale morphology has a weakening effect on the normal contact stiffness of the mating surfaces.

This paper provides an effective method for the multi-scale separation of the surface morphology and then lays a certain theoretical foundation for improving the surface quality of parts and the morphology design.

The purpose of this paper is to propose a new hybrid approach based on bibliometrics analysis (BA), morphology analysis (MA) and conjoint analysis (CA) to help identify new technology development opportunities.

A new hybrid approach based on BA, MA and CA has been conducted to help identify new technology development opportunities. The proposed hybrid process is illustrated with a case example of blue light‐emitting diode (LED) based on GaN.

In this paper, the proposed hybrid process is illustrated with a case example of document information from a blue light‐emitting diode (LED) based on GaN documents database. The results show that the configuration “Al₂O₃+MBE+two dimensional photonic crystal” should be given greater attention with respect to R&D activities in future.

This paper is of interest for technology opportunities analysis practitioners and policymakers at the industrial and government levels.

This paper proposes a new hybrid approach of technology opportunities analysis based on bibliometrics analysis, morphology analysis and conjoint analysis methods.

The purpose of this paper is to investigate the effect of different levels of place understanding (primarily typo-morphological analysis) on the nature of interventions within historic urban setting and buildings within the City of Amman.

The research methodology depended on an extensive thematic survey and analysis. The typo-morphological analysis addressed several of Amman's residential hills and their connections with the downtown area. The thematic place survey tool included different units of analysis (e.g. buildings, public spaces, streets and sloped lands between streets) and addressed the values of these various buildings and spaces, their typology, typo-morphology and relation to the urban context, nature of change and transformations over time to mention a few. The extensive survey also included semi-structured interviews about these buildings addressing their emergence, historic context and values.

The paper presents an architectural typology for Amman's architecture and its relationship with the city's morphology stressing the specificity of Amman's historic core and residential hills. The paper also discusses the effect of this level of place understanding on the nature and levels of interventions within historic settings and buildings.

This level of place understanding (typo-morphological analysis) can have a positive impact on the practice of architectural and urban conservation by informing the nature of interventions within historic urban setting and buildings within the city. More specifically, this level of place understanding can, first, inform the development of urban and heritage guidelines within conservation areas in one of Amman's residential neighborhoods (Weibdeh) and, second, inform the nature of interventions to existing historic buildings based on respect of building typology.

This paper contributes to the disciplines of architectural and urban conservation illustrating how place understanding can inform practices of heritage conservation and future policies and strategies concerning new intervention within such heritage places.

Informal dwellings describe makeshift lodgings made from temporary materials, such as plastic, corrugated iron, sheeting, packing cases, or wood. These units allow low-income groups to informally occupy land and create their habitable space in a phased manner. This article focuses on elements of the urban morphology, such as density, accessibility, and operating assortment of informally built areas in the southern region of Montenegro.

The author examines the urban morphologies of four urban areas, whose informality is traditionally viewed as markers of decline and despair. Using observations, questionnaires, and semi-structured interviews, the investigator maps dwellings in Ulcinj, Budva, Tivat, and Herceg Novi neighbourhoods. The researcher interrogated participants about land distribution during the construction of sheds, buildings' outline and orientation toward the street, and activities performed in their dwellings, such as living, working, and accommodating relatives and guests. This methodology tests the hypothesis, formulated as a deeper understanding of urban morphology for examining the interweaving of informally built settlements with the rest of the city.

A cartographic investigation is used to reframe customary rights of low-income populations to land inclusion and their place in the city. The results clearly show that the location and lifestyle are designed to obfuscate the vulnerable populations from the public view, disconnected from policymaking, and ignored by urban planning projects. However, the interviewees' destinations orientation away from the downtowns represents the possibility of reconfiguring existing urban planning practices. For creating alternative urbanisation, the orientation of less visible neighbourhoods presents a model for building regulations embedded in social forces and cultural habits of all social and ethnic groups.

This study did not address the implementation of social hosing policies and the logistical limitations of realising them by the local and national governments. During firework, the author encountered dwellers outside four studied low-income neighbourhoods in the south region of Montenegro. Mapping morphological elements of these generally small clusters of informal built units are left for future research. Future studies could examine how informality is performed in Montenegro by moderate and high-income groups as an assemblage of different power relationships and urban practices.

The argument is based on counter urbanism as the orientation and destination of less visible neighbourhoods for creating building regulations embedded in social forces and cultural habits of all social and ethnic groups. This study showed that the urban morphology of informality in the coastal cities of Montenegro lays the ground for alternative urban planning practices based on the different interconnection of districts. The outcome is a strong link between different social and ethical groups through self-building practices.

In coastal cities of Montenegro, Roma, Ashkali, and Egyptian live with other low-income groups in unsanitary settlements characterised by poor living conditions, low-quality illegally built housing, no plumbing or sewage systems, and overcrowded urban areas. Mapping morphological elements of less visible urban areas propose shifting from top-down urban planning policies to a participatory model of developing urban areas.

The assemblage of informally built urban areas legitimise place in the city that goes against the housing market's dominant logic and exceeds alternative logics of building production. This article outlined the urban morphologies of four urban areas for turning the image of informality away from decline and despair to lessons of urban interconnection. By creating different maps, the author presented a diverse orientation of four case studies based on density, accessibility, and operating assortment.

To investigate effects of the thermal history on intermetallic thickness and morphology and on the resulting shear strength of the ball attachment for a variety of BGA components.

In this study, a variety of BGA components with balls made of Pb‐free Sn‐Ag‐Cu (SAC) 305, Sn‐Pb eutectic and high‐temperature 90Pb‐10Sn alloys, were subjected to different thermal histories, including up to ten reflow cycles, and aged at 125°C from 24 to 336 h. The intermetallic thickness and morphology after these thermal events were then examined under optical and scanning electronic microscopes. Ball shearing tests were conducted to investigate effects of the thermal history and intermetallic thickness and morphology on shearing strength of these solder balls.

The results show that effects directly from intermetallic layers may or may not be detectable; and the shear strength of solder balls is largely dependent on the solder alloy and its microstructure. Shear strength increases are observed after multiple reflow cycles and ageing at elevated temperature for the two Pb‐bearing alloys, while the SAC305 lead‐free alloy shows slight reductions in both strength and ductility after thermal exposure.

Presented results can be used for estimation of reliability for electronic assemblies subjected to multiple rework and repair operations, which expose sensitive components, such as BGAs, to elevated temperatures.

It is believed that a sound understanding of the effects of intermetallic morphology and thickness on reliability of BGA solder balls can lead to more intelligent choice of soldering processes, as well as to rework/repair process optimisation and to establishing their operational limits.

The purpose of this paper is to compare electrochemical corrosion characteristics of conventional and unconventional fluoride conversion coating prepared on magnesium alloy.

The chemical reaction of AZ61 with 38 wt.% hydrofluoric acid (HF) for 24 h was used as a conventional way of fluoride conversion coating preparation. The unconventionally prepared coating was created in Na[BF₄] salt melt at 450°C for 2 h. Morphology and chemical composition of prepared fluoride conversion coatings were studied with scanning electron microscopy and energy-dispersive X-ray spectroscopy. Electrochemical corrosion characteristics of the coatings were analyzed in Hank’s solution using potentiodynamic tests.

Both the coating preparation ways resulted in the creation of uniform conversion coatings with the same thickness (1.3 ± 0.1 μm). Some defects were observed on the coatings surface; however, the defects did not reach the AZ61 surface. Electrochemical tests performed in Hank’s solution at 37°C showed an improvement of corrosion resistance of AZ61 treated with fluoride conversion coatings when compared to the untreated material. Unconventionally prepared coating reached better electrochemical corrosion characteristics when compared to the conventionally prepared coating.

Electrochemical corrosion characteristics of AZ61 magnesium alloy can be improved with fluoride conversion coatings. Two methods are used in the literature for the coatings preparation. The conventional method is based on dipping of the coated material to the HF, and the unconventional method lies in dipping of the sample to the Na[BF₄] salt melt. The main purpose of the present study is to analyze the conventionally and unconventionally prepared coatings in terms of chemical analysis, morphology and material corrosion protection (electrochemical corrosion characteristics), while the data are not provided in the literature, according to the authors’ knowledge. Very similar coatings were prepared using both the methods from the morphological and chemical composition point of view. However, unconventionally prepared coating created in Na[BF₄] salt melt reached better electrochemical corrosion characteristics compared to the coating prepared in HF.

The purpose of this paper is to detect the existence of unknown wireless devices which could result negative means to the privacy. The perceptual layer of internet of things (IoTs) suffers the most significant privacy disclosing because of limited hardware resources, huge quantity and wide varieties of sensing equipment. Determining whether there are unknown wireless devices in the communicating environment is an effective method to implement the privacy protection for the perceptual layer of IoTs.

The authors use horizontal hierarchy slicing (HHS) algorithm to extract the morphology feature of signals. Meanwhile, partitioning around medoids algorithm is used to cluster the HHS curves and agglomerative hierarchical clustering algorithm is utilized to distinguish final results. Link quality indicator (LQI) data are chosen as the network parameters in this research.

Nowadays data encryption and anonymization are the most common methods to protect private information for the perceptual layer of IoTs. However, these efforts are ineffective to avoid privacy disclosure if the communication environment exists unknown wireless nodes which could be malicious devices. How to detect these unknown wireless devices in the communication environment is a valuable topic in the further research.

The authors derive an innovative and passive unknown wireless devices detection method based on the mathematical morphology and machine learning algorithms to detect the existence of unknown wireless devices which could result negative means to the privacy. The simulation results show their effectiveness in privacy protection.

This paper aims to investigate the corrosion evolution process of AZ91 magnesium alloy in 3.5 wt.% NaCl solution under different stresses by using in situ methods, thereby evaluate the influence of stress on the corrosion sensitivity of AZ91 magnesium alloy, and discuss the potential mechanism.

A four-point bending method was used to apply different loads to the magnesium alloy samples, a charge coupled device camera and electrochemical impedance spectroscopy test being used for in situ study. Scanning electron microscopy and X-ray diffraction (XRD) analysis were performed for corrosion product and morphology characteristics.

The observation results show that the corrosion of AZ91 magnesium alloy becomes more and more serious with the increase in the stress and generated many corrosion products. Originally, corrosion products prevented alloy matrix from contacting the corrosive medium. However, the increase in the stress facilitated the emergence of the corrosion holes in the corrosion products, which provided the microscopic channels for corrosive solution to attack the Mg alloy matrix, and accelerated the corrosion of the magnesium alloy, resulting in a lot of corrosion pits on the magnesium alloy surface under the corrosion product layer.

The evolution information of corrosion process is crucial to explore the mechanism of corrosion. Currently, most researches about corrosion of magnesium alloy used traditional testing techniques to obtain corrosion information, lacking the direct tracking and monitoring of the corrosion evolution process. Hence, this paper focuses on in situ corrosion study of AZ91 magnesium alloy. The technology with spatial resolution capability observed the changes in magnesium alloy surface at different times in the corrosion process in situ. Meanwhile, the in situ electrochemical technology was used to monitor the changes in micro-electrochemical signals during the corrosion process of magnesium alloy under different stresses.

The anticorrosion coatings used in marine and atmospheric environment are subjected to many environmental factors. And the aging failure has been puzzling researchers. The purpose of this study is to find the correlation between the initial aging of epoxy coatings and the typical marine atmospheric environmental factors.

The epoxy coatings were subjected to a one-year exposure in three typical marine atmospheres. Meanwhile, principal component analysis, linear regression and Spearman and gray correlation analysis were applied to quantify the environmental characteristics and establish correlations with the coating aging.

The results indicate that the coating will undergo macroscopic fading and chalking upon exposure to the marine atmosphere, while microscopic examination reveals holes, cracks and partial peeling. The adhesion performance and electrochemical properties of the coating deteriorated with prolonged exposure, coating aging mainly occurs with the generation of O-H bonds and the breakage of molecular chains such as C-N and C-O-C. The coating was most deeply aged after exposure to the Xisha, followed by Zhoushan and finally Qingdao. Environmental factors affect the photooxidative aging and hydrolytic degradation processes of coatings and thus coating aging. To further demonstrate the correlation between environmental factors and coating aging, principal component analysis was used. The correlation model between environmental factors and coating aging was subsequently obtained. The correlation model between the rate of coating adhesion loss (E) and the comprehensive evaluation parameter of environmental factors (Z) is expressed as E = 0.142 + 0.028Z. Meanwhile, the Spearman correlation analysis and gray correlation method were used to investigate the impact of each environmental factor on coating aging. Solar irradiation, relative humidity and wetting time have the highest correlation with coating aging, which are all above 0.8 and have the greatest influence on coating aging; wind speed and temperature have the smallest correlation with coating aging, which are about 0.6 and have the least influence on coating aging.

This paper establishes a correlation between typical marine environmental factors and coating aging performance, which is crucial for predicting the service life of other coatings in diverse environments.