Effect of product structure on manual assembly performance

1995 ◽  
Vol 5 (2) ◽  
pp. 149-161 ◽  
Author(s):  
Girish V. Prabhu ◽  
Martin G. Helander ◽  
Valerie L. Shalin
Keyword(s):  
Product Structure ◽  
Manual Assembly ◽  
Assembly Performance

Effect of Product Structure on Manual Assembly Performance

1992 ◽  
Vol 36 (10) ◽  
pp. 729-732
Author(s):  
Girish V. Prabhu ◽  
Martin G. Helander ◽  
Valerie L. Shalin
Keyword(s):  
Structure Factor ◽  
Product Structure ◽  
Manual Assembly ◽  
Assembly Task ◽  
Hierarchical Assembly ◽  
Two Factors ◽  
Assembly Instructions ◽  
Product Structures ◽  
Instruction Strategies ◽  
Assembly Performance

Using Maynard's description, an assembly task may be divided into various task elements like reach, select, grasp, move, position, and assemble (Ghosh and Helander, 1985). Activities such as “reach” and “move” are governed by biomechanics of body motions including human factors principles such as Fitt's law. This research investigated the effect of the structure of the assembly and the type of assembly instructions on performance. Two different product structures were used — a vertical assembly, built bottom-up, and a hierarchical assembly, consisting of several subassemblies. Two different instruction strategies were used: 1. top-down sequential instructions 2. No Instructions. The research showed that vertical products were easier for manual assembly, when provided with instructions. For all three dependant measures, there was no interaction effect between the two factors, namely product structure and instructions. Average time for completion was significant for both factors i.e. product structures ( F(1, 20) = 4.417, p < 0.0485) and instructions ( F(1, 20) = 5.886, p < 0.0248). However, time for learning was significant only for product structure factor ( F(1, 20) = 5.239, p < 0.033). Also, trials to learn was significant only for product structure factor ( F(1, 20) = 4.449, p < 0.047).

scholarly journals Experimental investigation into aircraft system manual assembly performance under varying structural component orientations

2019 ◽  
Vol 234 (4) ◽  
pp. 840-855 ◽  
Author(s):  
David Judt ◽  
Craig Lawson ◽  
Helen Lockett
Keyword(s):  
Aircraft Wing ◽  
Vertical Orientation ◽  
Manual Assembly ◽  
Industrial Practice ◽  
Electric System ◽  
Hot Air ◽  
Work Tasks ◽  
Wing Structure ◽  
Aircraft System ◽  
Assembly Performance

Installation of aircraft wing systems is a bottleneck in the assembly process. This phase is typically composed of many work packages, taking hundreds of man-hours per wing. In addition to this volume of work, tasks are specialized and completed in a difficult environment in terms of access and visibility. In current industrial practice, the wing is mounted horizontally on a transport trolley, which exposes the workforce to prolonged periods of overhead working. Future wing designs may consider a pre-equipping build philosophy, where systems are installed to major structure assemblies before the wing box is assembled. This allows for a change in the orientation and position of the major structure and provides new freedoms in assembly station design and layout. This research presents results of experiments to investigate manual assembly performance of aircraft wing systems, under varying wing structure orientation. A mock-up of a section of an A320 aircraft wing front spar, mounted on a rotation device, functions as the testbed. Manual installation activities are then conducted to emulate real aircraft system equipping for electric harnesses, raceways and hot air ducts. The results show a best-case assembly performance change of 36% for electric system installation activities of cable harnesses and raceway housing components. Tilted and horizontal orientations of the structure show the highest time reductions, with the vertical orientation either non-conclusive or increasing the assembly time. The outcomes of this study are intended to aid in effective trade-off decision making for future wing systems and assembly station layouts from the perspective of structural orientation and assembly task interaction.

Unzipping Natural Products: Improved Natural Product Structure Predictions by Ensemble Modeling and Fingerprint Matching

2018 ◽  
Author(s):  
William A. Shirley ◽  
Brian P. Kelley ◽  
Yohann Potier ◽  
John H. Koschwanez ◽  
Robert Bruccoleri ◽  
...  
Keyword(s):  
Natural Products ◽  
Open Source ◽  
Natural Product ◽  
Gene Cluster ◽  
Public Domain ◽  
Product Structure ◽  
Fingerprint Matching ◽  
Ensemble Modeling ◽  
Chemical Structures ◽  
Source Gene

This pre-print explores ensemble modeling of natural product targets to match chemical structures to precursors found in large open-source gene cluster repository antiSMASH. Commentary on method, effectiveness, and limitations are enclosed. All structures are public domain molecules and have been reviewed for release.

On the Reaction of 2,5-Dihydroxy-[1,4]-benzoquinone with Diamines – Strain-induced Reactivity Effects

2020 ◽  
Vol 24 ◽  
Author(s):  
Hubert Hettegger ◽  
Andreas Hofinger ◽  
Thomas Rosenau
Keyword(s):  
Nucleophilic Substitution ◽  
Product Structure ◽  
Carbonyl Groups ◽  
Reaction Products ◽  
Double Bonds ◽  
Oh Groups ◽  
Natural Geometry ◽  
Quinoid Structure ◽  
Bond Localization

: The regioselectivity of the reaction of 2,5-dihydroxy-[1,4]-benzoquinone (DHBQ) with diamines could not be explained satisfactorily so far. In general, the reaction products can be derived from the tautomeric ortho-quinoid structure of a hypothetical 4,5-dihydroxy-[1,2]-benzoquinone. However, both aromatic and aliphatic 1,2-diamines form in some cases phenazines, formally by diimine formation on the quinoid carbonyl groups, and in other cases the corresponding 1,2- diamino-[1,2]-benzoquinones, by nucleophilic substitution of the OH groups, the regioselectivity apparently not following any discernible pattern. The reactivity was now explained by an adapted theory of strain-induced bond localization (SIBL). Here, the preservation of the "natural" geometry of the two quinoid C–C double bonds (C3=C4 and C5=C6) as well as the N–N distance of the co-reacting diamine are crucial. A decrease of the annulation angle sum (N–C4–C5 + C4–C5–N) is tolerated well and the 4,5-diamino-ortho-quinones, having relatively short N–N spacings are formed. An increase in the angular sum is energetically unfavorable, so that diamines with a larger N–N distance afford the corresponding ortho-quinone imines. Thus, for the reaction of DHBQ with diamines, exact predictions of the regioselectivity, and the resulting product structure, can be made on the basis of simple computations of bond spacings and product geometries.

scholarly journals Quasi-ideal Ehresmann transversals: The spined product structure

2021 ◽  
Vol 19 (1) ◽  
pp. 77-86
Author(s):  
Xiangjun Kong ◽  
Pei Wang ◽  
Jian Tang
Keyword(s):  
Structure Theorem ◽  
Product Structure ◽  
Abundant Semigroup ◽  
Spined Product ◽  
Equivalent Conditions

Abstract In any U-abundant semigroup with an Ehresmann transversal, two significant components R and L are introduced in this paper and described by Green’s ∼ \sim -relations. Some interesting properties associated with R and L are explored and some equivalent conditions for the Ehresmann transversal to be a quasi-ideal are acquired. Finally, a spined product structure theorem is established for a U-abundant semigroup with a quasi-ideal Ehresmann transversal by means of R and L.

scholarly journals Workplace Adaptive Technologies for Working Adults With Cognitive and Physical Disabilities

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 861-861
Author(s):  
Patricia Heyn
Keyword(s):  
Physical Disabilities ◽  
Cognitive Impairments ◽  
Work Productivity ◽  
Mobile Technologies ◽  
Individuals With Disabilities ◽  
Technology System ◽  
Working Adults ◽  
Assembly Performance ◽  
Adaptive Technologies ◽  
Assembly Tasks

Abstract Individuals with disabilities usually have difficulty in finding and maintaining employment prospects and thus, they are extremely underrepresented in the workforce. These challenges are even greater when the person has both cognitive and physical disabilities. While there is evidence supporting the benefits of employing individuals with disabilities in the workforce, employers are usually unprepared to hire individuals with disabilities. They are also concerned that the work productivity may be impacted by the employee with a disability. Thus, technology can play an important role in helping a person with cognitive and /or physical impairment work on tasks that require memorization and assembly performance. We will present a mobile technology system that was planned and piloted with working adults with physical and cognitive impairments. Founded on our pilot study, mobile technologies hold the potential to help people with disabilities to perform jobs that require memorization as well as systematic assembly tasks.

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