ORIGINAL RESEARCH ARTICLE | May 30, 2020
Effect of Relative Plate Thickness in the Heat Flow and Cooling Rate during Welding of Super Duplex Stainless Steel
André de Albuquerque Vicente, Roberto Luiz de Souza, Denise Crocce Romano Espinosa, Renato Rodrigues de Aguiar, Pexcin Paul, Amilton Barbosa Botelho Junior
Page no 244-250
Duplex stainless steels are characterized by their biphasic, ferritic-austenitic microstructure. The ideal volumetric fraction of these phases in duplex stainless steels, is of 50% ferrite and 50% austenite, however, this condition is difficult to be obtained when arc welding these materials. A detailed analysis of the effect of relative plate thickness in the heat flow and, consequently, in the cooling rate during welding of duplex stainless steel is of fundamental importance. The correct adjustment of the welding parameters leads to an optimum cooling rate of the joint, which guarantees a good balance of the volume fractions of ferrite and austenite, and results in acceptable mechanical properties and corrosion resistance. In this work, the best welding practices to the duplex stainless steel UNS S32750 (Super Duplex) were studied, guaranteeing welded joints that showed the ideal volumetric fractions of ferrite and austenite and, consequently, the mechanical properties according to the project. Complementary techniques of microstructural analysis were used, such as optical emission spectrometry, optical microscopy and quantitative image analysis.
REVIEW ARTICLE | May 4, 2020
Increased Sensitivity and Safety of Cognitive Robot by Developing Professional and Behavioral Skills
Page no 187-196
The paper highlights general approach to creating cognitive adaptive robots with imitative thinking and adaptive behavior as an assistant to humans in various fields of activity. Communicative-associative symbolic-language thinking logic allows the creation of cognitive adaptive robots for different spheres of life. Specialization of cognitive adaptive robots is carried out on the basis of knowledge bases, bases of abilities and implementers of behavior. Adaptive behavior is guided by imitative thinking on a human task and is carried out by models of environment and behavior. Specialization of the robot is set by the subject knowledge base and base of abilities, and equipment (sensors, sensors, manipulators, motor systems and other devices). For collaborative robotics, you need a soft, sensitive, and naturally highly intelligent solution. The focus here is on pneumatic light robots, which are inherently designed to work together and can present a cost-effective alternative to humans in the future. The cognitive robot, by increasing visual, sound, substantive, spatial and temporal sensitivity, is able to acquire new skills and accumulate experience of behavior with the necessary technical means. New skills are taught by a retraining system in virtual space, and then the robot develops them in a specific environment. Thus, the professional experience of the cognitive robot in various specific environments is gradually accumulated and its sensitivity is increased. Cognitive adaptive retractable robots with imitative thinking, adaptive behavior, and increased sensitivity have the prospect of widespread practical application.
ORIGINAL RESEARCH ARTICLE | May 7, 2020
Effect of Weight Stabilization before Curing of V-Belt
Abdul Kalam Azad John Mohamed
Page no 197-202
The aim of this method is to reduce the rejection rate in V-belt using weight stabilization method. Low Belt, Double Jacket, Topping Air, and Base Air are the major rejection in V-belt due to the dissimilar weight in V-belt as the weight plays a vital role in determining the quality of a product and processing parameter such as pressure and heat. The above problems can be rectified by taking weight during the final processing stage of V-belt subsequently it can be segregated depending upon the weight range before curing and then set the curing parameters. Another aspect of taking correct weight every time for the same length & cross section of belt is the regularity of dimension. I vehemently envisage that this method can be used to reduce the rejection rate based on dissimilar weight for any rubber based products not only the V-belt. The benefits of this method is extended below
• Sophisticated device are not required to implement this method.
• Products having uneven weight can be converted into defect free product.
• Rejection rate can be firmly controlled.
ORIGINAL RESEARCH ARTICLE | May 19, 2020
Identification of Causes of Delay in Road Projects: Cases in Gandaki Province, Nepal
Dhan Prasad Subedi, Buddhi Raj Joshi
Page no 231-243
The construction industry in Nepal is an important sector due to its enormous contribution to the country’s economic development. This in terms of employment opportunities and attraction of Foreign Direct Investments which grossly contributes to the country’s GDP. Due to various factors many construction projects are prone to delay. These delay factors can only be avoided by first identifying the factors and their sources. The objectives of this research were to find out the causes of delay and to find related importance in completed Road construction projects in SNRTP in Gandaki province in Nepal. The Relative Importance Index (RII) was used to rank the causes of delay. Similarly, reliability of research instrument was calculated using Cronbach’s coefficient alpha. The results obtained indicate that the top major causes of delay were; weather and climatic condition (RII=0.898), delay in decision in relocation of service (RII=0.886), long chain of hierarchical decision making process (RII=0.885), land acquisition/donation (RII=0.884), inaccurate time estimation, errors during construction (RII=0.884), conflict between joint ownership of the project (RII=0.872), poor communication and coordination between the participants (RII=0.836), lack of database and experience for estimating activity duration and resources required in a construction (RII=0.818) ,owner’s lack of experience and involvement (RII=0.809), shortage of materials /equipment (RII=0.807), improper project document management (RII=0.800), to least ranked consultant’s reluctance for change and their flexibilities (RII=0.722) .Finally the top major delay mitigating measures were; Information sharing and Joint risk management, Enhancing Contractual management and administration capability, Making timely decision in project, Managing sufficient time and allocation of adequate team for project preparation, Completing pre-execution preparation of project before project starting, Investigating/studying the site properly, strengthening the skill/capability of human resources and selecting better Time for contract.
ORIGINAL RESEARCH ARTICLE | May 19, 2020
Impact of Variation Orders on Construction Project Cost: A case study of Land Pooling Project at Kathmandu of Ichangu Narayan, Nepal
Aananda Raj Pokharel, Buddhi Raj Joshi
Page no 203-230
Government of Nepal has been planning to develop modern cities through land pooling programs as per the Town Development Act 2045. The study is conducted in Ichangu Narayan (Raniban) Land Pooling Project phase II and the status of variation orders, their origin, causes and impacts in project cost and completion time is analyzed to develop preventing measures which can be beneficial in upcoming similar projects. The objective of the research was to identify the types of variations and the origin and rank, to assess the impact of variation orders regarding cost and duration and to explore the preventive measures to minimize the variation orders. Primary data were collected from the questionnaire survey, key informant interview and field study. The secondary data were collected by means of desk study, relevant literature and text books review, maps and drawings and internet sources. From the study, main cause of variation orders impacting project completion time is known to be conflict between the contract documents and is originated from Consultant. Similarly, main cause of variation orders impacting project cost is additional work. 26.50% (Rs 45,700,255.02) cost above the contract cost has been incurred directly at the completion of the project. 12.40% (Rs 21,380,129.70) of contract cost has been paid for price escalation only. Similarly, 16.96% cost for the successive contract of the project has been increased by the extension of the contract duration. The appropriate recommendation has been given to the concerning parties involved in the construction work.
ORIGINAL RESEARCH ARTICLE | May 30, 2020
Vibration Analysis of Cracked Cantilever Beam with Varying Crack Length
Dr. Amit M. Patil, Amol M. Kolhe, Chetanraj D. Patil
Page no 251-257
Engineering structures such as plates, beams, and shells are subjected to different types of loads when used in applications such as bridges, buildings, and other structures. Due to the nature of loading cracks are produced in these elements over a period of time. These cracks will cause the failure of beams due to vibration. Vibration analysis is important to find the natural frequency of the structures. Modal analysis is performed to find the mode shapes and natural frequency of the cantilever beam. In the present investigation, a cantilever beam with crack is modeled and natural frequency for the first three modes is determined by using Ansys Workbench 19.2. The goal of the study is to change the length of the crack along the width of the beam and its effect on the natural frequency of the cantilever beam. During the study, the crack width is kept constant while the depth of crack is varied along with a change in the length of the crack. The crack with depth 45 mm and crack of length 50 mm gives a lower value of natural frequency.