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In plane elasticity, a general expression for a mutual work difference integral (MWDI) derived from two stress fields is introduced. Once two physical stress fields are known beforehand, the relevant MWDI can be evaluated exactly from the coefficients in the complex potentials. A biaxial tension model for evaluating defect energy is introduced. A particular MWDI from two fields, one is for the damaged medium under remote biaxial tension and other is for an infinite perfect plate under the same remote biaxial tension, can be defined as a suitable measure of stiffness for the damaged medium, which is called the defect energy ( E (a) ). The suggested model can deal with the cracks, holes, and elastic inclusions in a unique way. The model can also evaluate the defect energies for different damages exactly without dependence on the orientation of damages. Physically, the higher is the defect energy achieved, the more are the involved damages in the medium. The defect energy may be negative, which means a more rigid inclusion is included in the medium. For 3D‐elasticity, a triaxial tension model is introduced for evaluating the defect energy for the damaged medium. For some particular cases, for example, the dissimilar elastic spherical inclusion, or the elliptic flat crack, the relevant defect energies are evaluated.

The present experiments are intended to help characterize defects in very thin MOS oxide and at its Si/SiO₂ interface using a temperature‐dependent electrical characterization method, high low temperature capacitance voltage method and, especially, to investigate high temperature range. Oxide‐fixed traps are differentiated from slow‐state traps and from fast‐state traps by evaluating their electrical behaviour at different temperatures. The analysis points out the excess current after Fowler Nordheim electron injection based on hole generation, trapping, and hopping transport at high temperatures. The defect relaxation property versus temperature is investigated and defect relaxation activation energies are calculated. Creation mechanisms of interface states are especially identified by injection at different temperatures and these are compared with the other two kinds of defects. Fast‐state traps and all defect cross‐sections are calculated along and their creation activation energies are determined from Arrhenius plots.

The largest share of a building maintenance budget goes towards preventing or repairing building defects. Also, building defects shorten a building’s lifetime, impact the user’s safety and health, prevent the buildings from performing their functions well and repairing building defects generates waste. Therefore, this study aims to specify the factors that affecting the number of building defects and how to reduce their negative impacts.

A case study was used as a research strategy and convergent parallel mixed methods were used as research design. Quantitative and qualitative data were collected concurrently, followed by independent analyses of the quantitative and qualitative data, and then merged the two sets of results according to the procedure of using the convergent parallel design. Descriptive statistics analysed quantitative data, whilst qualitative data was analysed by the content analysis technique.

The findings of this study explored the factors that affect the number of defects in buildings, the significant factors were related to the building’s life cycle in terms of design, construction, operation and maintenance phase; relevant attributes were construction teams, building users and maintenance teams. The study also addressed the approaches to minimise the negative impacts of those factors. Their negative impacts mainly contributed to increased building defects that increase maintenance costs, affect users’ safety and health, reduce buildings’ lifespan and cause environmental impact due to resource extraction.

The existing studies have not adequately addressed the significant factors that affect the number of building defects. Also, emerging technologies and environmental sustainability considerations related to building defects have not been linked in previous related work. Therefore, the present study has contributed to filling this gap.

Developments in neutron detection technology during the past three years are reviewed with special emphasis on application to safety, security, or industrial development.An investigation about the possibility of using N‐channel power MOSFET (metal oxide semiconductor field effect transistor) as a high‐energy neutron sensitive detector is presented here. An empirical expression for neutron fluence detection is derived from the relation between neutron fluence and the evolution of the transistor current measured in the saturation region. This expression is valid for neutron fluence in the range 5×10⁹–1×10¹⁴ n cm⁻².

This paper aims to estimate the relationship between defect structure with gas concentration for use as a gas sensor. The change in defect concentration caused a shift in the Fermi level, which in turn changed the surface potential, which is manifested as the potentiometric response of the sensing element.

A new theoretical concept based on defect chemistry and band structure was used to explain the experimental gas response of a sensor. The theoretically simulated response was compared with experimental results.

Understanding the origin of potentiometric response, through the generation of defects and a corresponding shift in Fermi level of sensing surface, by the adsorption of gas. Through this understanding, the design of a sensor with improved selectivity and stability to a gas can be achieved by the study of defect structure and subsequent band analysis.

This paper provides information about various types of surface defects and numerical simulation of material with defect structure. The Fermi energy of the simulated value is correlated with the potentiometric sensor response.

Gas sensors are an integral part of vehicular and industrial pollution control. The theory developed shows the origin of response which can help in identifying the best sensing material and its optimum temperature of operation.

Low-cost, reliable and highly sensitive gas sensors are highly demanded which is fulfilled by potentiometric sensors.

The operating principle of potentiometric sensors is analyzed through electron band structure analysis. With the change in measured gas concentration, the oxygen partial pressure changes. This results in a change in defect concentration in the sensing surface. Band structure analysis shows that change in defect concentration is associated with a shift in Fermi level. This is the origin of the potentiometric response.

The purpose of this paper is to improve the performance and quality of Ti-6Al-4V fabricated by laser powder bed fusion.

Single-track experiments were conducted during the fabrication process to obtain the single tracks with excellent wettability to narrow the process parameter window. The effects of process parameters on the build surface, cross-section, relative density, defects, surface roughness, microstructure and mechanical properties of the parts were analyzed through multilayer fabrication experiments and surface optimization experiments.

The point distance has the greatest influence on the build surface of the fabricated parts, and the unmelted defects can be eliminated when the point distance is 35 µm. The relative density of the fabricated parts decreased with the increase of the point distance, and the hatch spacing has different characteristics with respect to the relative density of the fabricated parts under different laser powers. It was observed that the most of experimental groups with higher relative densities than 99%, and the highest density could reach 99.99%. The surface roughness can be reduced to less than 10 µm through remelting optimization.

The research results can provide theoretical support for scientific researchers and data support for engineers.

The purpose of this paper is to investigate and classify the defects on silicon-based power devices under extreme conditions.

Electrical characterization was performed on MOS devices to study their interface defects. The devices were subjected to a voltage or a current constraint to induce defects, and then measurements were done to detect the effects of those defects. Measurements include current voltage, capacitance and conductance characterization. The Hill–Coleman method was used to calculate the interface states density in each case.

It was found that most of the defects have energies within the upper band gap of the semiconductor.

The method used in this paper allows the determination of any interface defects on a Si/SiO₂ structure.

The purpose of this study is to investigate the microstructural evolution of high-strength 2024 Al alloy prepared by the laser powder bed fusion (L-PBF) additive manufacturing (AM) route. The high-strength wrought Al alloy has typically been unsuitable for AM due to its particular solidification characteristics such as hot cracking, porosity and columnar grain growth.

In this research work, samples were fabricated using L-PBF under various laser energy densities by varying laser power and scan speed. The microstructural features that developed during the solidification are correlated with operating laser parameters. In addition, finite element modelling (FEM) was performed to understand the experimentally observed results.

Microstructure evolution and defect formation have been assessed, quantified and correlated with operating laser parameters. Thermal behaviour of samples was predicted using FEM to support experimental observations. An optimised combination of intermediate laser power and scan speed produced the least defects. Higher energy density increased hot tearing along the columnar grain boundaries, while lower energy density promoted void formation. From the quantitative results, it is evident that with increasing energy density, both the top surface and side wall roughness initially reduced till a minimum and then increased. Hardness and compressive strength were found to decrease with increasing power density due to stress relaxation from hot tearing.

This research work examined how L-PBF processing conditions influence the microstructure, defects, surface roughness and mechanical properties. The results indicates that complete elimination of solidification cracks can be only achieved by combining process optimisation and possible grain refining strategies.

The purpose of this paper is to present defects reported by cooperative owners, and to determine the relationship between building characteristics, developer’s/contractor’s company size and defect type.

The analysis is based on defects reported by board members of cooperatives in Sweden through a survey questionnaire. The 1,563 questionnaires were posted by regular mail to the boards of cooperatives for buildings. The current research presents results from analysis of responses from 394 regular residential projects constructed between 2006 and 2013. The responses represent owners’ experience from a total 1,107 buildings.

Findings presented in this study indicate that building quality might be one of the factors contributing to the energy gap. The analysis indicates that the most severe problems reported by cooperatives are issues related to building envelope, particularly shortcomings in the function of windows, issues related to the function of the balcony and cracks in the facade and leakage caused by rain water. The results show that the building quality differs depending on developers’ size, measured by number of employees. The authors have also found a significant relationship between reported defects and location expressed by size of the city/municipality.

The discussion on newly constructed residential buildings has been dominated by the perspective of professionals (inspectors) and contractors (or developers) rather than of the owners/users themselves. This study presents findings from the owners’ perspective, thus contributing the owners’ viewpoint to the debate on building quality.

The purpose of this paper is to supplement and upgrade existing research on LPBF of NiTi alloys. Laser powder bed fusion (LPBF) is a promising method for fabricating nickel–titanium (Ni–Ti) alloys. It is well known that the energy density is mainly adjusted through the scanning speed and laser power. Nevertheless, there is lack in research on the effects of separately adjusting the scanning speed and laser power on the properties of the final Ni–Ti components. On the other hand, although Ni-rich Ni–Ti alloys [such as Ni54(at.%)Ti] have great potential in structural applications because of their high hardness and good shape stability, at present, there are few studies focusing on this grade of Ni–Ti alloy.

In this work, the energy density was adjusted by changing the laser power and scanning speed separately, and the corresponding process parameters were used to fabricate Ni54(at.%)Ti alloys. The formability (including the relative density, impurity content, etc.) and tensile properties of the LPBF Ni54(at.%)Ti alloys fabricated with different combinations of process parameters were analyzed.

The effects of increasing the laser power and reducing the scanning speed on the properties of the LPBF Ni54(at.%)Ti alloys and the property differences between components manufactured with different combinations of laser power and scanning speed under the same energy density were analyzed. The optimal process parameters were selected to fabricate the components that achieved the highest ultimate tensile strength of 537 MPa, a high relative density of 98.23%, a relatively low impurity content (0.073 Wt.% of carbon and 0.06 Wt.% of oxygen) and an ideal pseudoelasticity (95% recovery rate loaded at 300 MPa).

The effects of increasing the laser power and reducing the scanning speed on the properties of LPBF Ni54(at.%)Ti alloys were studied in this paper. This work is an upgrade and supplement to the existing research on fabricating Ni-rich Ni–Ti alloys by the LPBF method.