Small Lot Research Articles

Design of a test rig for the characterization of friction and wear in hot-metal gas-forming of AA 5083 aluminium sheets

Advanced aluminium sheet-forming processes such as the hot-metal gas-forming represent a challenging solution for producing small lots in the high-end car bodies industry, and the adoption of single cavity moulds made from low-cost, easily machinable materials such as cast iron reduces the overall sheet-forming costs. The tribological properties of the mould-sheet tribopair are of great interest for optimizing the sheet forming obtaining an acceptable esthetic surface finishing. This study presents the design and construction of a lab-scale experimental test rig for the tribological characterization at high temperatures of the mould-sheet tribopair. The proposed test method reproduces the sliding at the mould-sheet interface with contemporary sheet straining up to ε = 0.8 at strain rates in the 1.2*10-3 to 2*10-2 s-1 range. A series of experiments were carried out in dry and lubricated conditions for a ductile iron EN-GJS grade sliding against a AA 5083 aluminium alloy while straining. After comparing the experimental results with the literature data from other test rigs, comparable results were obtained as COF regards, ranging between 1.2 to 2.5 in dry sliding and between 0.05 to 0.2 in lubricated sliding. The morphological characterization of the sliding surfaces and cross-sections highlights the strong tendency to galling in dry sliding conditions expecially for low strain rates.

Old and New Vallila. The early years of affordable housing production in Helsinki

ABSTRACT Vallila is a showcase of Finnish social housing at the beginning of the twentieth century. Old wooden Vallila was built 1908–1915. It consisted of 22 small building lots, all meant to be built as one family houses by standardized drawings. As times were poor, the population grew out of control. In 1908, Bertel Jung started his work as the first town planning architect of Helsinki. He signed the first town plan for New Vallila in 1913, aiming at a clearly urban environment. Houses of three to four floors height were regulated by detailed facade schemes. Trees and greenery were respected in New stone Vallila and some blocks were built around private courtyards (Swedish name: storgårdskvarter). The biggest and most impressive of them is the block 555, started in 1916 as a company dwelling, and finished as a semi-communal project in 1929. The architects were Armas Lindgren and Bertel Liljequist. During the 1920s townscape was internationally in the spotlight, and Finnish architects followed keenly Nordic and German examples. They read and travelled a widely. Contacts with Swedish colleagues brought the peculiar dwelling type of landshövdingehus from Gothenburg to New Vallila. Italian architecture gave faith in the ever-lasting value of classicism.

Prediction of forming accuracy in incremental sheet forming using artificial neural networks on local surface representations

While incremental sheet metal forming offers the potential for producing sheet metal parts in small lot sizes, the relatively low forming accuracy prevents widespread industrial use. For improving the forming accuracy, research institutes are using machine learning techniques to predict the geometric accuracy and modify the toolpath based on the prediction. A critical challenge is it to ensure the generalizability of the prediction model as only a small amount of process data is available to train the model due to the lack of industrial collaborations. This publication presents a highly transferable feature engineering approach where surface representations of the part’s geometry around each toolpath point are transferred into a standardized coordinate system. Several artificial neural networks were trained and used for predicting the forming accuracy and modifying the toolpath. During the validation experiments, the forming errors of parts which were independent of the training process were reduced by up to 68.5 %. The framework for computing the surface representations alongside with several pre-trained artificial neural networks is publicity available for download.

Analyzing the Factors of Vacant Home Occurrence for Urban Sustainability: A Case Study of Medium-Sized Cities Focusing on Asan City, Chungcheongnam-do

This study aims to enhance urban sustainability by analyzing the spatial distribution and underlying causes of vacant homes in Asan, Chungcheongnam-do. Various statistical methods were employed to analyze date concerning the number of vacant stores, population changes, land use complexity, and the physical characteristics of land and buildings; these factors were found to influence the prevalence of vacant homes across Asan. Additionally, it was found that distinct factors differentially affect specific regions, such as old downtown areas versus rural villages. This indicates that reducing vacant homes in these areas requires distinct policies tailored to the unique circumstances of each region. For instance, in old town areas, small lot ratios and land use complexity are significant, while in rural villages, the average number of floors and land use complexity play a major role. This study highlights the diverse factors influencing the prevalence of vacant homes and suggests that to effectively address this issue, policies should be developed that are tailored to the unique characteristics of each area, categorized at both the city and local levels.

Thermal Performance Analysis of Affordable House in the Equatorial Coastal Area of the Tropics

Affordable housing subsidised by the government in Indonesia often poses many problems, including an uncomfortable internal environment that leads to the massive use of mechanical ventilation. Designing an affordable house undoubtedly faces challenges due to the very small building lots, while it should provide many spatial needs and functions for the occupants’ daily activities. Because of limited funding provided by the government, affordable house design is often based only on basic needs, thus scarcely considering thermal comfort for the occupants. This study evaluates the thermal performance of affordable houses built for the 2018 great earthquake, tsunami, and liquefaction victims in Palu’s coastal area. Field measurements were conducted in an affordable housing complex, and a sample house was selected, representing a raised floor house design prototype. External and internal climate conditions were recorded for nine days to establish the hourly thermal trend. Hobo Onset H21 microclimate stations were used to record external climate conditions, whereas Onset Hobo U12-012 T-RH-Light was employed to record internal thermal conditions. The result showed that the thermal condition in the sample house was intolerably hot. The main cause of these conditions is the design of the roof and building envelope. The selected materials with a high U-value also worsen the thermal conditions in the sample house

A case study of whale optimization algorithm for scheduling in C2M model

With the continuous upgrading of industrial technology and information technology, consumers can deeply participate in the whole life cycle of products and realize customized production. These unprecedented changes have brought consumers and manufacturers closer together, resulting in the intelligent business model of "Internet + Customized Production" and "Customer to Manufacturer (C2M)". C2M has been adopted by more and more companies. However, the transition from traditional business models to C2M is a problem that every company must face and solve. Personalized orders of many varieties and small lots put enormous pressure on the production of mainly labor-intensive electronic assembly companies. The theoretical findings of Industry 4.0 and Lean Manufacturing show that people play a central role in assembly operations. As an important element of the production system, worker scheduling has a direct impact on delivery time and cost. Worker scheduling requires not only matching people to jobs, but also considering flexible employment. According to the "Learning Curve" theory, workers with learning potential can continuously enrich their skills and work efficiency will show dynamic changes. Therefore, under the condition of shortest order delivery time and lowest cost, worker scheduling considering the learning effect becomes a challenge for enterprise decision makers. Firstly, the production method of manufacturing industry in C2M environment is studied. Then, based on single-skill task and multi-skill task, respectively, a learning curve-based model of dynamic change in worker skill level is constructed. And this model is used as the input of the assembly line worker scheduling model. Secondly, an Elite Non-dominant Sorting Whale Optimization Algorithm (ENS-WOA) is designed for this multi-objective optimization problem. The correctness and feasibility of the proposed algorithm are verified by selecting classical arithmetic cases for experimental comparison with other algorithms. Finally, the established worker efficiency change model, worker scheduling model and the proposed algorithm are applied to optimize the assembly line of water pump products of Company B, which is being transformed to C2M, and solved by MATLAB software. The results show that the model proposed in this paper is effective, stable and practical compared with the worker costs and delivery period required to complete the order in the original assembly line. Worker costs were reduced by 29.02% and orders were completed approximately 10 days earlier.

Indigenous knowledge in agroforestry promotion: a case from Bandegaun, Indrawati Rural Municipality, Sindhupalchok District, Nepal

This research presents the role of indigenous traditional knowledge on agroforestry promotion in Bandegaun of Sindhupalchok district. Both primary and secondary information was collected through a household survey, key informant discussion, focus group discussion, direct observation, and review of agroforestry-related literature, papers, and reports. Agriculture was the main occupation of the respondents with the majority (62%) of the total respondents having a small landholding of less than 0.75 ha. However, about 91% of the total had practiced both agri-silviculture and home gardening, 55% of the total respondents had a Silvi-pastoral system and 27% of the total respondents had a small wood lot of trees. The main indigenous traditional knowledge used by the respondents for the promotion of these agroforestry practices in their farms were knowledge on the palatability of fodder species, knowledge on timber quality, knowledge on propagation by cutting, knowledge on NTFP value, knowledge on cash earning, and knowledge on religious value of tree species. A total of 39 tree species were included in the agroforestry practices of the study areas. Among them were 10 fodder species, 12 timber and fuelwood species, 6 NTFPs, and 11 fruit trees. Each study household on average have grown 4 fruit trees, 47 fodder tree, 19 fuelwood, and timber trees, and an NTFP in their farmlands, which have provided a great contribution to fodder, fuelwood, and timber supply for household use reported by 91% of the total respondents and some respondents (76%) had also generated income from the sale of timber, fuelwood, and NTFPs. Finally, it is recommended that indigenous knowledge-based agroforestry awareness and training programs along with preferred seedlings of good quality should be provided to promote agroforestry in study areas.

Private-led land assembly and urban consolidation: The relative influence of regulatory zoning mechanisms

From the time a city is first subdivided, its structure of lots act as a precursor to all future redevelopment, forming the spatial bounds of land ownership that force buildings to develop and evolve in their place. It is therefore critical for planning systems that intend to contain urban sprawl to encourage the lot superstructure to adapt to the emerging needs of a city. This study assesses the role that existing regulatory planning mechanisms play in directing the spatial distribution and frequency of private developer-led land assembly. Drawing on two inner city local government areas in Melbourne, Australia, this research analyses the relative influence of local zone-led development controls on the occurrence of land assembly over an eleven-year period. A descriptive spatial analysis and global logistic regression model reveal that an interplay of maximum height restrictions, existing plot boundaries, and sales prices, have led to a disordered distribution of parcel amalgamations. A geographically weighted logistic regression model highlights spatial variation in the influence of these factors, with small lots in the inner city being subject to the least influence of development controls. The results are supplemented by a small sample of interviews with local planners and developers, who suggest that regulatory planning controls inadvertently turn desired built form outcomes into a tool for capital appreciation and landowner holdouts. In combination, the findings suggest that zone-led development controls do little to influence market forces in a manner that induces private-led land assembly in favour of the public good.

Assessing the lean-green practices in the automotive industry: Perspectives from academia and industry

Since the emergence of rising environmental issues, firms urgently require a supply chain strategy that will allow them to compete effectively in the marketplace. Implementing lean and green supply chain management strategies have been recommended to achieve sustainability and competitiveness. Yet, there is some ambiguity about how these practices must interact with one another. While lean practices have been around for a while and are widely adopted by businesses, the green movement is still evolving in the supply chains for most industries. This paper aims to identify the most important lean-green practices in supply chain management and their relative importance to firms’ sustainable performance in automotive industry context using Best Worst Method. The results reveal that green related practices are the most important to achieve environmental, economic, and social performance respectively. Whereas most lean practices remain the least important. As mentioned by the results three green practices, namely Environmental Management System (EMS), Green Purchasing (GP), and Reduce, Reuse and Recycle (3R), are the most important, while Small Lot Sizing (SLZ) is the least important lean practice. These practices contribute to the improvement of environmental, economic, and social performance respectively. The findings of this research offer a theoretical and empirical roadmap for decision makers seeking to identify key practices that are most likely to contribute to improving various aspects of sustainable performance in automotive context.

Limitations of science and intolerance

Modern sciences have some limitations, from scarcity of resources for experimentation to non-availability of data. In the vast universe of “hypotheses not tested,” we have a small lot of proven theories. What is considered as a proven theory is based on certain assumptions; besides they can be colored by the intentions of financers. Truth evolves. Professionals can be proud of achievements but they should not be proud of the principles, which are falsifiable by definition.

Towards live decision-making for service-based production: Integrated process planning and scheduling with Digital Twins and Deep-Q-Learning

Production flow is becoming increasingly complex since manufacturers must react quickly to changing markets demands and diverse customer requirements. In order to ensure production efficiency, it is essential to have an adequate scheduling system capable of managing diverse process flows and handling unforseen changes. In this paper, we present an approach leveraging Digital Twins (DTs) and Deep-Q-Learning to perform integrated process planning and scheduling for service-based production. DTs of production assets provide live information about their physical entities for our approach to perform live decision-making based on the current operation conditions. We use Deep-Q-Learning which is a deep Reinforcement Learning (RL) algorithm to perform integrated process planning and scheduling. We present two RL-designs that deal with different situations of live decision-making. We have evaluated the learning efficiency and scalability of the RL-designs on a virtual aluminum cold rolling mill developed by the SMS Group,11https://www.sms-group.com/plants/cold-rolling-mills-for-aluminum. in the context of the BaSys 4.2 project.22https://www.eclipse.org/research/projects/basys_42/. The results show that the first RL-design is suitable for deriving schedules for individualized production with small lots where process plans must be re-calculated frequently, while the second RL-design is optimal for production with large job quantities where jobs arrive continuously.

E-commerce warehousing: An efficient scattered storage assignment algorithm with bulky locations

The problem of assembling a large number of heterogeneous time-critical customer orders from a wide range of products is one of the biggest challenges that E-commerce retailers are currently facing. Unlike the traditional warehouses that could hardly keep up with the surge in demands brought by the e-commerce boom, internet fulfillment warehouses (IFWs) are designed to suit such a fast-paced environment for handling sales and customer orders of online retailers, and scattered storage is one of the trending storage assignment strategies adopted by many of them. Under the scattered storage strategy, the newly arrived items are exploded into a bunch of small stocking lots and purposely scattered around the entire warehouse. Such an assignment strategy enhances the probability of always having a nearby location containing the requested item. Thus, it potentially shrinks the order fulfillment time. This paper presents a novel scattered storage assignment approach suited for IFWs operations. Compared with the existing literature, this assignment approach pays more attention to handling the inevitable quantity fluctuation of customer ordering patterns. The proposed problem is mathematically expressed as a MIP model, and a heuristic algorithm, consisting of a feasibility checking procedure and a two-stage item allocation procedure, is developed to generate a high-quality solution in a time-efficient manner. Numerical studies are then conducted to assess the computational performance of the proposed algorithm and to justify if the proposed model is efficacious and improves order-picking efficiency.

Analysis of the 2007-2008 Hérault premiumized grubbing-up campaign: a tool to better understand Fischer-Boel’s 2008-2011 grubbing-up campaigns and the desire in 2022 to reintroduce locally premiumized grub-ups

The objective of this article is to study the microeconomic motivations of the grubbing up of vines by analyzing of application files and a survey in a department in the south of France, Hérault, the year before the 2008/2009 campaign, which implements the European grubbing up program of 175,000 hectares of vines. Only one French department and one campaign are evaluated: Hérault and 2007/2008. Our originality is the analysis of a subset consisting of 341 Viniflhor applications for grubbing up premiums, which represents 20% of all beneficiaries receiving premiums. The applications were later sent with the applicants’ consent to a development agency. Within this subset, we selected 51 grape growers with whom we conducted a qualitative and quantitative survey. Our goal was to identify their real motivations for grubbing up their vines. We first undertook a historical review of Europe’s grubbing up policy and of older research analyzing in detail this question such Pierre Bartoli’s 1982 thesis. We also included studies of the Observatoire de l’Hérault (Dyopta) that take into account experts’ opinions and statistical viewpoints. This review enables us to present the main indicators that let us “objectively” analyze these grub ups. We then put forward synthesized results explaining the qualitative interviews. Altogether they confirm the goals of the European Commission that were to incite non-profitable older grape growers, working on small land lots to grub up the entirety of their farms. But joined to the aforementioned are many other farms that grubbed up only a small fraction of their vineyards mainly to cash in on the premiums in times of a dire wine crisis. Grubbing ups of young “improving varietals” reinforces this analysis.

Sustainable technology for remanufacturing of carburized steels by laser hardening

The development of functional recovery technology for surface treatments is crucial for remanufacturing—a key green innovation technology for achieving a carbon-neutral, circular economy. Laser hardening (LH), a type of surface treatment method, is known to be able to reform the partial surface of metals. This study focuses on the use of LH to allow the repair of friction-fatigue damage in used carburized martensite steel gears. As the surface of the fatigued specimen was rapidly heated by the laser and then cooled, the thin hardening layer quenched the surface layer. In addition, prior austenite (γ) grain refinement and restoration of the retained austenite phase in the LH quenched layer were realized for the friction-fatigued specimen. Exploiting these characteristics, the friction-fatigued specimens were reheat-treated with LH; as a result, the number of cycles to failure increased by 3.8 times compared to that before LH treatment. For remanufacturing as a small lot production of many products, the LH technique incurs lower environmental and processing costs than other surface treatments and is particularly beneficial when applied to gears and bearings, which are especially susceptible to wear and tear.

Simulation Evaluation of Vehicle Movement Model Using Spatio-Temporal Grid Reservation for Automated Valet Parking

Automated valet parking (AVP) systems aim to use automated driving technology to park a vehicle from the passenger’s boarding/exiting location to a parking space in a parking lot and recall the vehicle from the parking space to the boarding/exiting location. For multiple vehicles to move efficiently through a parking lot, travel must be mediated between each vehicle. We have proposed a driving control method that improves the efficiency of AVP by using the Spatio-Temporal Grid Reservation mechanism. We previously compared it with an autonomous driving, which showed that the proposed method improved the efficiency of vehicle movement when vehicles are entering small parking lots. In this paper, we modified our previous method to accommodate the increasing number of vehicles in a parking lot and created Spatio-Temporal Grid Model as a vehicle movement model. we evaluate this model by comparing it with Conflict Zone Model and MAPF Model created by the methods proposed in related studies, in addition to an autonomous driving model. We performed simulations varying the percentage of vehicles arriving at the parking lot and showed that Spatio-Temporal grid model improves the efficiency of vehicle movement when vehicles are entering and exiting the lot.

Enhancing SLM Stainless Steel: Model-Based Parameter Optimization

SLM (selective laser melting) has faced challenges in ensuring consistent mechanical properties for various geometries. However, the authors have developed a system that solves this issue by calculating the optimal process parameters for each scan vector on each layer. This approach ensures consistent melt pool geometry, derived from the most robust parameters in conduction welding mode. The results from the single melt-line experiments and the presented thermal conduction solver demonstrate the effectiveness of this approach in achieving a stable melt pool geometry in stainless steel (1.4404 or 316L). Furthermore, a testing regimen has been developed to evaluate the system under different changing boundary conditions, to further demonstrate its usefulness. By utilizing this system, manufacturers will achieve consistent and high-quality mechanical properties which improves cost-effectiveness for small lot sizes, including spare and obsolescent parts.

Effect of Step Size on the Formability of Al/Cu Bimetallic Sheets in Single Point Incremental Sheet Forming

Single Point Incremental Forming (SPIF) is an unconventional forming process that is suitable for prototype production and small lot production due to the economical tooling cost, short lead time, and the ability to create symmetrical and asymmetrical complex geometries without the use of expensive dies. This article presents the effect of the step size Δz of a forming tool made of 145Cr6 tool steel on the formability and maximum forming angle, mechanical properties, hardness, surface roughness, microstructure and texture of bimetallic Al/Cu sheets. Experiments were conducted at a constant rotational speed and feed rate, with the use of rapeseed oil as a lubricant. The tests were carried out with the use of a forming tool on both sides of the bimetallic sheet. The shape and dimensions of the formed elements are determined by non-contact optical 3D scanning. It has been proved that an increase in the step size Δz affects the deterioration of the surface quality of the specimens (an increase in the Ra parameter from 0.2 μm to approximately 3 μm for the step size of 1.2 mm), while a small step size down Δz favours the geometric stability of the samples. With increasing step size (at Δx = Δy = const.), the drawpiece wall continually thinned until the material fractured. Based on the results, it was shown that increasing the step size Δz over 1.1 mm causes cracking of the drawpieces. Furthermore, greater thinning of the Al/Cu sheet was observed in the range of step size Δz between 0.7 and 1.0 mm for aluminum side and step size Δz ≤ 0.6 mm and Δz ≥ 1.1 mm for copper side. It was also found that the mechanical properties of the bimetal sheet decreased as a result of incremental forming. The greatest decrease in strength and ductility was recorded for a pitch of 1.2 mm. Strength decreased from 230 MPa (for sheet in initial state) to approximately 80 MPa, elongation from 12% to approximately 8.5%, and hardness from 120 HV10 for Cu and 60 HV10 for Al to approximately 30 HV10 for both layers.

Precision Low-Cost Compact Micro-Displacement Sensors Based on a New Arrangement of Cascaded Levers with Flexural Joints

Existing displacement sensors of micrometers to sub-micron precision are expensive and have various limitations. This paper reports the design and development of a new contact type compact micro-displacement sensor of sub-micron precision for a fraction of the cost of commercial devices. The basic concept of the new sensor system applies a mechanical magnifying mechanism to magnify a displacement at sub-micron to micron level and uses a low-cost Hall sensor to measure the magnified displacement. Various conceptual designs for the mechanical magnifying mechanism based on cascaded levers with flexural joints were studied and a final design, featuring side-by-side placement of lever structures in a multi-planar layout with adjacent levers coupled by L-shaped coupling foils, was devised. Prototypes of two different sizes and constructions with mechanical magnification ratios over 100 were made and tested. Measurement repeatability and accuracy to sub-micrometer level and a resolution down to hundredths of a micrometer were demonstrated by a compact Alpha Model prototype. Design modification of parts and a corresponding small lot size production procedure were devised to provide an estimated bill of material cost per unit under US$100.

A simultaneous balancing and sequencing algorithm to plan assembly lines in the fashion industry

PurposeThe purpose of the study is to fill a gap in the literature on mathematical production planning (joint balancing and sequencing) in the fashion industry. It considers in particular situations of mass customization, made-to-measure or small lot sizes.Design/methodology/approachThe paper develops a mathematical model based on product options and attributes instead of fixed variants. It proposes an easy-to-use genetic algorithm to solve the resulting optimization problem. Functionality and performance of the algorithm are illustrated via a computational study.FindingsAn easy-to-implement, yet efficient algorithm to solve the multi-objective implementation of a problem structure that becomes increasingly relevant in the fashion industry is proposed. Implementation of the algorithm revealed that the algorithm is ideally suited to generate significant savings and that these savings are impervious to problem and thus company size.Practical implicationsThe solutions from the algorithm (Pareto-efficient frontier) offer decision-makers more flexibility in selecting those solutions they deem most fitting for their situation. The computational study illustrates the significant monetary savings possible by implementing the proposed algorithm to practical situations.Originality/valueIn contrast to existing papers, for the first time, to the best of the author’s knowledge, the focus of the joint balancing and sequencing approach has been applied in the fashion instead of the automotive industry. The applicability of the approach to specific fields of the fashion industry is discussed. An option and attributes-based model, rarely used in general assembly line sequencing per se, is used for more flexibility in representing a diverse set of model types.

A forgotten cirripedological gem: a new species of whale barnacle of the genus Cetopirus from the Pleistocene of the United States West Coast

ABSTRACTA small lot of fossil whale barnacles from the Upper Pleistocene of California and the Middle Pleistocene (Chibanian) of Oregon (United States West Coast), described in a 1972 unpublished MA thesis, are formally described and illustrated herein. In that thesis, a new genus and species name were proposed; however, according to the International Code of Zoological Nomenclature, they have no taxonomic standing and are thus unavailable. Based on our reappraisal, two specimens in this lot belong to a new, extinct species that can be assigned to the purportedly extant genus Cetopirus. Cetopirus polysyrinx sp. nov. differs from congeners in that its secondary T-shaped flanges are multitubiferous internally, that is, they are perforated by a high number of irregularly-sized and irregularly-spaced tubules that result in a spongy aspect in transverse section. Whether or not this peculiar condition had any adaptive significance is difficult to determine. Considering that Cetopirus is currently known as an obligate epibiont of right whales (including the North Pacific form Eubalaena japonica (Lacépède 1818)), the host of C. polysyrinx sp. nov. was E. japonica or some other species of Eubalaena. The Plio-Pleistocene deposits of the Pacific coast of North America have yielded a rather idiosyncratic fossil whale barnacle fauna, inclusive of the genera Cetolepas, Cryptolepas and now Cetopirus, which seemingly contrasts with all other coeval assemblages worldwide, the latter being in turn dominated by Coronula spp.