-
Optimal Scheduling for a Service Technician Workforce with Time-varying Work Volume and Technician Availability
Issue:
Volume 2, Issue 6, December 2017
Pages:
77-82
Received:
30 May 2017
Accepted:
5 July 2017
Published:
7 November 2017
Abstract: A practical scheduling method is developed and implemented to determine the optimal allocation of technicians to candidate tour types and start times in a field service environment. Historical data is aggregated to determine a weekly work volume distribution and technician availability profile. These and other quantitative factors populate a mixed integer programming model for determining the distribution of technician tours that will minimize queueing delay in completing service, subject to side constraints on tour type quantities. The approach has been successfully implemented to schedule installation and maintenance technicians at a major telecommunication service provider and could easily be adapted to other operational contexts.
Abstract: A practical scheduling method is developed and implemented to determine the optimal allocation of technicians to candidate tour types and start times in a field service environment. Historical data is aggregated to determine a weekly work volume distribution and technician availability profile. These and other quantitative factors populate a mixed ...
Show More
-
On Comparative Analysis of Measure of Indifference of Process Parameters in Minimizing Surface Roughness of Drilling Mild Steel, Stainless Steel and Brass
Raimi Oluwole Abiodun,
Tanimola Babatunde Adedoyin
Issue:
Volume 2, Issue 6, December 2017
Pages:
83-86
Received:
8 October 2017
Accepted:
18 October 2017
Published:
20 November 2017
Abstract: The use of optimal parameter values in an experimental investigation for minimizing surface roughness has always been the design trend of many machining operation without checking the variation levels of the process parameters if it has any measure of significant difference or not in minimizing surface roughness of the workpiece. The study carried out a comparative analysis between low, intermediate and high level of cutting speed, feed, depth of cut and tool on mild steel, stainless steel and brass using one-way ANOVA approach with the aid of statistical package for social sciences (SPSS), version 17 based on drilling operation. The findings revealed that there were no statistically significant differences between the levels for the respective workpiece in minimizing surface roughness. The result implies that the low, intermediate and high level plays equal contributing effect in minimizing surface roughness in drilling mild steel, stainless steel and brass. The study concludes that preference should not only be given to a particular level in an experimental investigation because minimum surface roughness can be achieved at any level which we might least expected.
Abstract: The use of optimal parameter values in an experimental investigation for minimizing surface roughness has always been the design trend of many machining operation without checking the variation levels of the process parameters if it has any measure of significant difference or not in minimizing surface roughness of the workpiece. The study carried ...
Show More
-
Viscosities of Binary Liquid Mixtures of 1, 2-Dichloroethane with Pyridine, Dimethyl Sulfoxide, Acetone, Furan and Tetrahydrofuran at 303.15 K
Atri Deo Tripathi,
Asim Ahmad
Issue:
Volume 2, Issue 6, December 2017
Pages:
87-92
Received:
11 March 2017
Accepted:
6 April 2017
Published:
29 November 2017
Abstract: Kinematic Viscosities, ν at T=303.15K, have been measured for binary liquid mixtures of 1, 2-dichloroethane with pyridine, dimethyl sulfoxide (DMSO), acetone, furan and tetrahydrofuran (THF). The values of ν have been fitted in appropriate equations using a least squares method. The values of the quantity Δν, which refer to the deviations of the experimental values of the dynamic viscosities of the mixtures from the mole fraction mixture law values, have been calculated. Further analysis has indicated that McAllister’s approach correlates ν of the investigated mixtures all over the entire composition range to a appreciably high degree of accuracy.
Abstract: Kinematic Viscosities, ν at T=303.15K, have been measured for binary liquid mixtures of 1, 2-dichloroethane with pyridine, dimethyl sulfoxide (DMSO), acetone, furan and tetrahydrofuran (THF). The values of ν have been fitted in appropriate equations using a least squares method. The values of the quantity Δν, which refer to the deviations of the ex...
Show More
-
Modeling Assessment on Technological Challenges Facing Small-Scale Gold Miners in Tanzania and How Engineering Could Solve Them
Issue:
Volume 2, Issue 6, December 2017
Pages:
93-97
Received:
8 February 2017
Accepted:
24 February 2017
Published:
11 December 2017
Abstract: This paper aims on assessing the effects associated to the challenges facing small-scale miners in Tanzania. Small scale mining in Tanzania is characterized by low productivity which is mainly a result of application of rudimentary and inappropriate technology which in turn impact on capacities to generate income. The choice of technology among small scale miners is largely influenced by the lack of capital. In order to get gold, small scale miners typically have to excavate the earth and extract gold rich ores, pull the ores from the pits, carry them to the crushing machine, crush them, sieve the sand and lastly extract gold from the sand by using mercury. Each of the stages mentioned above involve a ton of technological challenges which, if solved could improve productivity and subsequently the lives of small scale miners in the country. However, this study focuses on the costs of that economic growth in gold production over small-scale miners. It is estimated that in the early 1990s, Small-Scale Mining in gold accommodated around 400,000 people in Tanzania. Due to a lack of hard data, this study was based on mostly qualitative fieldwork in Chunya district, Mbeya region, Tanzania. The research investigates how technological challenges can affect small-scale gold miner’s livelihood, focusing on those who depend, or have depended only on small-scale mining activities.
Abstract: This paper aims on assessing the effects associated to the challenges facing small-scale miners in Tanzania. Small scale mining in Tanzania is characterized by low productivity which is mainly a result of application of rudimentary and inappropriate technology which in turn impact on capacities to generate income. The choice of technology among sma...
Show More
-
Grid-Connected Control System for Three-Phase Bidirectional DC/AC Converter to Exploit Photovoltaic Power Generation
Le Tien Phong,
Do Trung Hai
Issue:
Volume 2, Issue 6, December 2017
Pages:
98-107
Received:
17 November 2017
Accepted:
27 November 2017
Published:
20 December 2017
Abstract: A grid-connetected control system is proposed in this paper to regulate three-phase bidirectional DC/AC converters in distribution grid exploiting photovoltaic power generation and not having energy storage at the DC side. To interact power flow at two its sides, statbilize voltage at the DCbus and synchronize with the grid, it includes an inner current controller and an outer voltage controller in a cascaded structure. Using small signal modeling and information about voltage at the point of common coupling and DCbus, control parameters for controllers are determined to balance power between photovoltaic system side and grid side. Simulation results show that the grid-connected control system helps the three-phase bidirectional DC/AC converter meet all requirements very well due to the balance of power at its sides to hold voltage at DC side at a fixed value, grid synchronization and low harmonic distortion total for current and voltage waveforms. They also represents the capability to exploit maximum available power of photovoltaic power generation under any operational condition.
Abstract: A grid-connetected control system is proposed in this paper to regulate three-phase bidirectional DC/AC converters in distribution grid exploiting photovoltaic power generation and not having energy storage at the DC side. To interact power flow at two its sides, statbilize voltage at the DCbus and synchronize with the grid, it includes an inner cu...
Show More
