Aisle Width Research Articles

Изнашивание обрезиненных валов кожевенных машин

When processing large skins, pinch rubberized rollers of leather machines must provide a sufficiently uniform pressure along the entire length of the shaft, as the thickness of the skins can vary up to 8 mm and more. The distribution of additional pressure is also affected by the buckling of the pinch and knife shafts, thus, with the aisle width greater than 2 m, additional factors affecting the wear of the roller surface must be considered. The article presents the results of experimental research into the wear of rubberized rollers as employed under factory conditions.

Development of quantitative tools for the design of an automated distribution center

Abstract This paper deals with the design of a warehouse or distribution center (CD). The number of doubled-sided racks, the height and the width of bays and aisles are calculated by closed-form formulas so that the distance traveled by an automated guided vehicle (AGV) and / or a human operator driving a hand cart, is minimized. The formulas developed allow the construction of the CD in the three dimensions, so that the cost of displacement is minimized. The main contribution of this work is the delivery of three-dimensional formulas for warehouses using an ABC type of scheme of general layout with easy-to-apply formulas. Other works present some difficulties in obtaining direct formulas since they need to solve a nonlinear minimization problem with linear constraints, forcing the use of iterative methods. In this work, such difficulty is resolved by using a Lagrangian function transforming the problem into one of unconstrained minimization.

물류센터에서 VNA 지게차로 대체시 경제성 분석모형

Tae-Seong Kim ․Cho-Won Kim ․Suk-Chul RimDepartment of Industrial Engineering, Ajou UniversityVNA(Very Narrow Aisle) forklift trucks require narrower aisle width than traditional counter-balanced trucks do because only the fork assembly turns in the aisle instead of the entire body of the truck. Substituting the VNA trucks for the existing counter-balanced trucks will result in the significant increase of revenue due to the increased storage capacity in the distribution centers. In this study, we present an economic analysis model for the substitution, in which we present a closed-form equation for the number of racks to stay unmoved, while maximizing the additional storage capacity; and resulting payback period of the substitution. A case study shows the payback period of only 8.1 months, indicating that this substitution is very profitable.

Detailed Dynamic Layout Planning: An Adaptive Layout Approach

Layout planning deals with the arrangement of facilities in a plant. Layout planning is said to be dynamic when the problem deals with the design of multi period plan with changes in demand. This paper formulates the dynamic layout problem as a quadratic assignment problem. An adaptive approach is considered to solve the problem. Simulated annealing is proposed for the development of solution in the form of a block plan for the dynamic plant layout problem. Addition of details such as flow plans, aisle width, department input /output location, etc. to the block plan gives a new detailed layout called net aisle and department layout. An integer linear programming model is used for the formulation of this detailed layout. A LINGO program is developed to solve the model. Net aisle and department layout provide a more realistic layout than a block layout with a better estimation of material handling cost.

Development of a Table-top Cultivation System for Robot Strawberry Harvesting

Cultivating a greenhouse strawberry system for a harvesting robot should help profitability by boosting yields and labor-saving. We have developed a high-density cultivation system utilizing movable hanging beds that hold 1.5 times the number of plants of conventional table-top systems. With the proposed system, nine beds could be placed in a greenhouse 8 m wide, whereas only six beds would fit into a conventional system. The hanging beds move parallel to each other on a two-wheeled frame travelling on a greenhouse beam approximately 2 m above the floor. Although the usual greenhouse aisle width between strawberry beds is 0.5 m, this automatically expands to approximately 1 m when the robot enters the aisle. The operation is currently performed manually by pressing a switch. The strawberry yield achieved with the mobile system was 1.5 times that obtained with fixed hanging beds. Our next project involves developing a low-clearance moving platform on which a robot can move.

Reliability of a Survey Tool for Measuring Consumer Nutrition Environment in Urban Food Stores

Despite the increase in the volume and importance of food environment research, there is a general lack of reliable measurement tools. This study presents the development and reliability assessment of a tool for measuring consumer nutrition environment in urban food stores. Cross-sectional design. A racially diverse downtown portion (6 ZIP code areas) in Albany, New York. A sample of 39 food stores was visited by our research team in 2009 to 2010. These stores were randomly selected from 123 eligible food stores identified through multiple government lists and ground-truthing. The Food Retail Outlet Survey Tool was developed to assess the presence of selected food and nonfood items, placement, milk prices, physical characteristics of the store, policy implementation, and advertisements on outside windows. For in-store items, agreement of observations between experienced and lightly trained surveyors was assessed. For window advertisement assessments, inter-method agreement (on-site sketch vs digital photo), and inter-rater agreement (both on-site) among lightly trained surveyors were evaluated. Percent agreement, Kappa, and prevalence-adjusted bias-adjusted kappa were calculated for in-store observations. Interclass correlation coefficients were calculated for window observations. Twenty-seven of the 47 in-store items had 100% agreement. The prevalence-adjusted bias-adjusted kappa indicated excellent agreement (≥0.90) on all items, except aisle width (0.74) and dark-green/orange colored fresh vegetables (0.85). The store type (nonconvenience store), the order of visits (first half), and the time to complete survey (>10 minutes) were associated with lower reliability in these 2 items. Both the inter-method and inter-rater agreements for window advertisements were uniformly high (intraclass correlation coefficient ranged 0.94-1.00), indicating high reliability. The Food Retail Outlet Survey Tool is a reliable tool for quickly measuring consumer nutrition environment. It can be effectively used by an individual who attended a 30-minute group briefing and practiced with 3 to 4 stores.

Calculating Evacuation Times from Lecture Theatre Type Rooms Using a Network Model

This paper presents a series of trial evacuations from several university campus lecture theatres. The results from the trial evacuations are compared against simulations using a Monte Carlo network evacuation model. Data from a number of literature sources from lecture theatre type rooms is then used to further compare the predictions from the model. Results show that the model gives reasonable predictions when the constrictions provided by either the exit doors or the aisle widths are accounted for. The inclusion in the model of a reduction in maximum movement speed due to the rows of seats is found to give a general overprediction.

Estimating picker blocking in wide-aisle order picking systems

In designing an Order Picking System (OPS) with multiple pickers, the designing (or selection) of several parameters (e.g., width of aisles, storage system and picking strategy) is dependent on the blocking that occurs between pickers. In this paper analytical models to estimate blocking in an OPS that has picking aisles wide enough to allow pickers to pass other pickers in the aisle are developed. In such OPSs, pickers can experience blocking at a pick face when two or more pickers need to pick at the same pick face. The developed models are compared with simulation, with results indicating that the proposed models are sufficiently accurate. Test results suggest that when pickers pick one SKU at a pick face, blocking is less in a wide-aisle OPS compared to that in a narrow-aisle OPS. However, when pickers pick more than one SKU at a pick face, blocking increases monotonically with an increase in the number of SKUs picked. The last result is significant since it highlights the importance of the proposed model that considers the variation in the time the picker is stopped to pick. [Supplementary materials are available for this article. Go to the publisher's online edition of IIE Transactions for the following free supplemental resources: (i) Appendix A, which describes the procedure to obtain a closed-form expression for b 1(2); (ii) Appendix B, which describes the derivations of the distributions for the case when pickers pick one SKU and pick:walk time ratio is ∞:1; and (iii) Appendix C, which describes the derivations of the distributions for the case when pickers may pick more than one SKU and pick:walk time ratio is ∞:1.]

AUTONOMOUS ROBOTIC VEHICLE DEVELOPMENT FOR GREENHOUSE SPRAYING

Application of nutrients, fungicides, and pesticides is one of the most important processes in agriculturalproduction and can have a significant impact on yield, quality, and ultimately profitability. However, fungicide and pesticideapplication can create significant environmental and human safety concerns. The motivations behind the development of anautonomous vehicle for greenhouse sprayer applications are to improve chemical delivery, reduce labor requirements, andminimize labor hazards. This research focuses on the development of a prototype vehicle platform that can be used ingreenhouse sprayer applications. A six-wheel differential steering vehicle was designed and built to act as a greenhousesprayer. Power was transmitted from two independent DC drives to the wheels through chain and sprocket transmission. Afuzzy logic-based proportional-derivative controller was developed to navigate the vehicle through simulated greenhouseaisles using range information provided by ultrasonic sensors. The vehicle was tested on sand and concrete surfaces usingtwo modes of operation. In self-contained mode, the vehicle carried a self-contained spraying system, while in trailer mode,the spraying system was mounted on a pull-behind trailer that was towed down the aisle. Results show that the self-containedmode performed better than the trailer mode on both sand and concrete. There was an average RMS path error less than 2.5 cmfor an aisle width of 61 cm and an instantaneous average error less than 6.4 mm. The robotic sprayer successfully navigated45.7 cm, 50.8 cm, and 61.0 cm aisle widths.

Routing policies and COI-based storage policies in picker-to-part systems

The paper evaluates and compares the expected travel distance for different routing strategies- namely traversal and return policies in low-level pickerto-part systems. Items are assigned to storage locations on the basis of the ratio of the required space to the order frequency (cube-per-order index or COI). The focus is on narrow-aisle systems, in which the distance travelled crossing the aisle from one side to the other is negligible compared to the distance travelled along the centreline of the aisle. For both routing policies, an efficient COI-based stock location assignment strategy is first developed. Second, analytical models are derived which relate the expected travel distance required to fill an order to the main system parameters (i.e. the COI-based ABC curve; the number of picks in a tour; the number, length and width of aisles). Simulation results confirming the accuracy of the analytical models are presented. Finally, preference regions as a function of the number of picks in a tour and differently skewed COI-based ABC curves are given for traversal and return policies.

An AutoCAD-Based Expert System For Plant Layout

Abstract This paper describes the development of a plant layout system implemented in AutoLISP on an IBM PS/2 computer. This system combines computational algorithms, human expertise, and computer graphics in one program for plant layout design and drafting. The objective is to develop a computer system for automation of the layout design and documentation process. This system emulates a plant layout expert in the last step of plant layout process. The input to the system includes department dimensions, between-department material flows, and aisle width. The system generates and evaluates layout alternatives according to given objectives. AutoCAD commands are called to plot the layout when an alternative layout is being created. This system ensures that each department has an access to the aisle and the travel distance between two departments are measured along the aisle. As both design expertise and computer graphics are programmed in the same environment, the interfacing problem between them is easily eliminated.

Computer aided design of unit loads

The unit load design problem includes the selection of the best pallet or container size, the best pallet or container layout, and the best number of parta per pallet or container. Three different approaches to solve the unit load design problem are identified in this paper and a new procedure is proposed: Computer Aided Design of Unit Loads (CADUL I). Using CADUL I, unit loads are designed considering system constraints (i.e., rack opening dimensions, aisle width, trailer-truck container dimensions, product crushability constraints, material handling equipment stacking capability and weight capacity) and a cost function that includes handling, storage, transportation, and pallet or container costs. An example is used to illustrate how CADUL I works and how these approaches to unit load design perform sensitivity analysis to validate the results obtained.

Order Picking In An Aisle

Abstract A classical order picking problem is the case where items have to be picked from both sides of an aisle and the picker cannot reach items on both sides without changing position. Hence the picker must cross the aisle one or more times. An efficient optimal algorithm is developed and shown to yield policies with up to 30% savings in travel time over commonly used policies. It is also shown that, for most practical aisle widths, it is significantly more efficient to pick both sides of the aisle in the same pass (a traversal policy) rather than pick one side and then pick the other side (a return policy) unless the pick densities are greater than 50%. All the algorithms presented here can be implemented in real time on a microcomputer.

Mobile Agricultural Research Laboratory is Designed for Operator Comfort

Studies of changes in vegetable quality during commercial handling require extensive periods of research at production locations to measure initial physical and chemical characteristics. When working in open air facilities it was found that required accuracies could not be maintained and that some procedures could not be completed. High temperatures, wind, dust, and other adverse environmental conditions severely reduced human and equipment performance. The success of mobile facilities ranging from medical clinics to bookmobiles suggested the possibility of a mobile laboratory for on-site agricultural research. The value of Human Factors principles was recognized for designing a general purpose research laboratory. A large (2.44 m X 9.75 m) cargo trailer was purchased to give the space and durability needed for repeated trips lasting several days. In addition to laboratory space, living facilities were needed for up to three researchers while at remote field sites. The completed mobile laboratory performed superbly on several trips in 1982 and 1983. Users of the lab compared it to a small but efficient kitchen which verified the value of attention to arrangement (work triangle, offset work stations, cabinet locations, etc.) and anthropometric principles (aisle width, counter height, adjustable stools, knee well dimensions, ceiling height, etc.). Productivity in the mobile laboratory was higher than in a modern laboratory in a Food Science building; possibly due to shorter distances between work materials and the presents of only necessary equipment. Quantitative measurements showed the mobile laboratory conformed to established limits for environmental factors. An air conditioner and a furnace maintained the interior within ASHRAE specified exposure limits dispite a 5°C to 40°C outside temperature. An exhaust fan with 4.53 m3/min capacity provided adequate ventilation (10 air changes per hour as recommended for laboratory type space). Illumination was adequate for general office work (1076 lux) and for highly difficult inspection task (2153 lux) at the work stations when using either battery powered or generator powered fluorescent lamps. Noise and vibration problems from the 10,000 watt electrical generator were minimized by placing it outside the laboratory on special vibration isolators. Vibrations from an air compresser were isolated by mounting it on the generator frame. Acceleration measurements at the sleeping section and at the work stations had a predominate frequency of 60 Hz. Measured acceleration values corresponded to ISO exposure limits (fatigue scale) ranging from 3.5 to 7.0 hours. Lack of fatigue symptoms after 10 hours exposure could be due to factors such as conservative standards, periodic movement, and reduced vibration under field conditions. A small battery powered water pump mounted under the sink caused noticeable vibration during short periods of operation. Background noise outside the laboratory (50.7 dBA) was reduced to 35 dBA with windows and doors closed. Operating the generator and air conditioner increased the noise level to 72 dBA. No speech interference was noticed for people at extreme ends of the laboratory. Outside the laboratory the noise level was 87 dBA at 1.83 m from the generator which is less than the 90 dBA eight hour exposure limit guideline given in The Walsh-Healey Act. A substantial improvement in working conditions has been realized by developing a mobile research laboratory. Human factors principles were found to be very beneficial when making design decisions and evaluating the finished unit. Common sense judgments were also needed when principles conflicted or compromises were necessary between economic considerations and the optimum design from the human factors point-of-view. It is certain that the use of established principles and standards minimized expensive rework that could have otherwise been necessary due to unacceptable noise and vibration levels.