This paper aims to study the energy consumption and quality characteristics of the parts fabricated by additive manufacturing (AM) technologies with a special focus on metal AM processes. AM is a family of manufacturing techniques, which is broadly used to fabricate complex and lightweight structures. The energy savings during AM processes have a significant influence on the AM industry, only if the quality of the fabricated part meets the requirements. The quality is generally represented by the surface and dimensional quality, mechanical properties, relative density, hardness, etc. The energy saving is important for environmentally benign and cleaner production, and improved product quality is useful for its application as a functional part in the aerospace, automobile, and biomedical industries. A comprehensive review of the energy consumption and quality characteristics of AM-fabricated (with special focus on metal AM) parts was carried out. Firstly, the specific energy consumption of various AM techniques has been reviewed to address the importance of energy and cleaner production. Then, the qualifications of products fabricated by different metal AM techniques have been discussed for different materials, such as titanium alloys, steel alloys, nickel alloys, and aluminum alloys. Also, by considering the practical importance of thin-walled structures fabricated by AM, a detailed analysis of their qualification has been presented. Moreover, different optimization techniques have also been reviewed for various AM process parameters and objectives. Overall, this paper provides an overview of AM, including a survey on the energy consumption and quality characteristics with the development of AM technologies for manufacturing of quality products. Finally, several future research directions are suggested, specifically the need for a framework for metal AM processes for the fabrication of quality products with minimum energy consumption.

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Few empirical studies have been conducted to explore what motivates and demotivates customers to engage in word of mouth (WOM) activities in the restaurant industry. This research paper inspects the connection between different attributes of hospitality industry which lead to the creation of word of mouth. A self-administered questionnaire was used to collect. 200 respondents from one of the leading and famous university of Pakistan is used as a sample to study on. To test the proposed model, we use structural equation modelling. The research ended with two major findings. First, food quality and service quality have great impact on creation of WOM. Second, price and atmosphere does not have any impact in creation of word of mouth.

The fully dense thin-walled structures are very important for manufacturers and customers. Selective laser melting (SLM) is mainly employed for the fabrication of thin-walled and lightweight structures of aluminum alloys, titanium alloys, etc. The goal of the paper is to study the effect of heat treatments, i.e., solution heat treatment (SHT) and artificial aging (AA) on the densification and porosity of the thin-walled specimens. Thin-walled specimens with various wall thicknesses (i.e., from 0.50 to 5.0 mm) were fabricated using AlSi10Mg alloy powder with optimal process parameters on the SLM system. The relative densities of the heat-treated specimens were compared with the as-built test specimens. The porosity development during the process and their relationship with the relative density are also studied critically by applying Archimedes' method and optical microscopic analysis. Results showed that the densification and porosity distribution behavior is changing with the variations in the wall thickness of specimens. The lowest relative density of 93.42% was obtained for 1.50-mm-wallthickness specimen in SHT condition. The maximum relative density of 98.61% was achieved for 5.0-mm-wall-thickness specimen in the AA condition. Finally, it is concluded that the AA has a significant influence on the low-wall-thickness (i.e., from 0.50 to 2.0 mm) specimens, and the densification is improved, and porosities are reduced due to fine grain structure and strong bonding between particles.

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