Assembly Time Research Articles

Fabrication of Bingöl pollen self-assembled monolayer films on copper as a novel cathode for electrochemical hydrogen production

Preparation of a thin organic film on metallic electrodes can protect substrates against corrosion. These organic underlayers also help electrodeposition of metallic electrocatalysts as well as enhance the quality and performance of electrodes. In this study, a thin self-assembled monolayer film of Bingöl pollen (BP-SAM) was fabricated on a copper substrate (Cu/BP-SAM) in pure water as solvent. The film was prepared by exposing a Cu substrate to a 1000 ppm aqueous pollen solution for 24 h assembly time. Then, a small amount of Ni, known for its good catalytic properties for water splitting process, was electrodeposited over the previously assembled SAM film (Cu/BP-SAM/Ni) to enhance its catalytic effect for hydrogen evolution reaction. The modified surfaces were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), and contact angle (CA) studies. Water splitting activity of the Cu/BP-SAM and Cu/BP-SAM/Ni electrodes were investigated in 6 M KOH solution at 298 K. The data obtained indicated that the modification of Cu surface with BP-SAM and BP-SAM/Ni reduces polarization resistance (Rp) by 35.3% and 84.4%, respectively at −100 mV cathodic overpotential. The BP-SAM films were adherent to the Cu substracte and have a uniform structure. Ni particles were homogenously deposed over the SAM film and have high quality. The Cu/BP-SAM/Ni electrode has promising electrochemical time-stability during the electrolysis and losses only 6.5% of its activity during the long-time electrolysis.

Extracellular Matrix Deposition Defines the Duration of Cell Sheet Assembly from Human Adipose-Derived MSC

Cell sheet (CS) engineering using mesenchymal stromal cells (MSC) draws significant interest for regenerative medicine and this approach translates to clinical use for numerous indications. However, little is known of factors that define the timing of CS assembly from primary cultures. This aspect is important for planning CS delivery in autologous and allogeneic modes of use. We used a comparative in vitro approach with primary donors’ (n = 14) adipose-derived MSCs and evaluated the impact of healthy subject’s sex, MSC culture features (population doubling time and lag-phase), and extracellular matrix (ECM) composition along with factors related to connective tissue formations (α-SMA and FAP-α) on CS assembly duration. Using qualitative and quantitative analysis methods, we found that, in seeded MSCs, high contents of collagen I and collagen IV had a direct correlation with longer CS assembly duration. We found that short lag-phase cultures faster turned to a ready-to-use CS, while age, sex, fibronectin, laminin, α-SMA, and FAP-α failed to provide a significant correlation with the timing of assembly. In detachable CSs, FAP-α was negatively correlated with the duration of assembly, suggesting that its concentration rose over time and contributed to MSC activation, transitioning to α-SMA-positive myofibroblasts and ECM turnover. Preliminary data on cell density and collagen I deposition suggested that the TGF-β1 signaling axis is of pivotal importance for ECM composition and construct maturation.

Applications for CO2 lasers in the automotive industry

AbstractSince the inception of the moving production line by Henry Ford in 1913, automotive manufacturers have continuously pursued process optimization to reduce costs and enhance profits by minimizing assembly times. In contemporary automotive production, automation is pervasive, and robots have become integral to manufacturing processes. To further improve efficiency and versatility, lasers have emerged as indispensable tools, supplanting conventional methods and offering numerous advantages in the automotive manufacturing landscape.

INSPIRE: INvestigating Stellar Population In RElics – V. A catalogue of ultra-compact massive galaxies outside the local Universe and their degree of relicness

ABSTRACT This paper presents the third data release of the INvestigating Stellar Population In RElics (INSPIRE) project, comprising 52 ultra-compact massive galaxies (UCMGs) observed with the X-Shooter spectrograph. We measure integrated stellar velocity dispersion, [Mg/Fe] abundances, ages, and metallicities for all the INSPIRE objects. We thus infer star formation histories and confirm the existence of a degree of relicness (DoR), defined in terms of the fraction of stellar mass formed by z = 2, the time at which a galaxy has assembled 75 per cent of its mass, and the final assembly time. Objects with a high DoR assembled their stellar mass at early epochs, while low-DoR objects show a non-negligible fraction of later formed populations and hence a spread in ages and metallicities. A higher DoR correlates with larger [Mg/Fe], supersolar metallicity, and larger velocity dispersion values. The 52 UMCGs span a large range of DoR from 0.83 to 0.06, with 38 of them having formed more than 75 per cent of their mass by z = 2. Of these, nine are extreme relics (DoR>0.7), since they formed the totality ($\gt 99~{{\ \rm per\ cent}}$) of their stellar mass by redshift z = 2. The remaining 14 UCMGs cannot be considered relics, as they are characterized by more extended star formation histories. With INSPIRE we built the first sizeable sample of relics outside the local Universe, up to z ∼ 0.4, increasing the number of confirmed relics by a factor of >10, and opening up an important window to explain the mass assembly of massive galaxies in the high-z Universe.

Are the fates of supermassive black holes and galaxies determined by individual mergers, or by the properties of their host haloes?

ABSTRACT The fates of massive galaxies are tied to the evolution of their central supermassive black holes (BHs), due to the influence of AGN feedback. Correlations within simulated galaxy populations suggest that the masses of BHs are governed by properties of their host dark matter haloes, such as the binding energy and assembly time, at a given halo mass. However, the full picture must be more complex, as galaxy mergers have also been shown to influence the growth of BHs and the impact of AGN. In this study, we investigate this problem through a controlled experiment, using the genetic modification technique to adjust the assembly history of a Milky Way-like galaxy simulated with the EAGLE model. We change the halo assembly time (and hence the binding energy) in the absence of any disruptive merger events, and find little change in the integrated growth of the BH. We attribute this to the angular momentum support provided by a galaxy disc, which reduces the inflow of gas towards the BH and effectively decouples the BH’s growth from the halo’s properties. Introducing major mergers into the assembly history disrupts the disc, causing the BH to grow ≈4 × more massive and inject feedback that reduces the halo baryon fraction by a factor of ≈2 and quenches star formation. Merger events appear essential to the diversity in BH masses in EAGLE, and we also show that they increase the halo binding energy; correlations between these quantities may therefore be the result of merger events.

Addressing Challenges in Dual Sided SiP Thermal Budget

System-in-Package (SiP) has been adopted as the mainstream advanced packaging technology in many consumer applications including 5G smartphones, tablets, wireless earbuds, smart wearables, etc. Heterogeneous integration, smaller form factor, better electrical performance, lower cost of assembly and faster time to market are the key differentiators of SiP as compared to conventional packaging techniques. In applications such as 5G mobile RF Front-End (RFFE) and Antenna-in-package (AiP) modules, dual sided SiP is the popular approach which brings even higher level of integration and smaller form factor. However thermal warpage control is a significant challenge during two times of solder reflow processes for the front and back sides of the package, especially if one side is with underfill and mold materials which have significant CTE mismatch to the substrate and dies, causing delamination failures and yield losses. This study examines the novel solution of reducing thermal budget with the use of a low temperature solder paste material based on SnBiAg alloy in ultra-fine pitch Type 6 solder powders. It allows a minimal peak reflow temperature of only 170 °C that effectively reduces warpage of dual sided SiP substrates. Solder alloy and paste properties and solder joint microstructures are examined in detail for tests including fine-pitch printing and component soldering, thermal aging test on different substrate finishes, thermal cycling test and mechanical drop test for reliability performance.

Long-term creep monitoring of composite wing leading edge using embedded fiber Bragg grating

The creep behavior of composite wing leading edges resulting from nonequilibrium residual stresses and material viscoelasticity needs to be evaluated comprehensively as it significantly affects assembly. In this study, long-term creep monitoring of a composite wing leading edge used in an actual airplane for 710 h is conducted using embedded fiber Bragg grating arrays and a creep extraction algorithm. The spectra and Bragg wavelength shifts of two embedded arrays, which involve temperature, thermal expansion, and creep, are recorded and analyzed. The creep curve of the composite wing leading edge is reconstructed and further predicted using the creep extraction algorithm based on multiparameter decoupling and the Burgers model. This study elucidates the enlargement of the opening size in the composite wing leading edge by measuring the tensile strain above the neutral axis. The predicted creep time serves as a valuable reference for determining the appropriate assembly timing.

One-point quadrature of higher-order finite and virtual elements in nonlinear analysis

In the present article, a stability- and consistency-preserving integration scheme for polynomial Galerkin approaches of arbitrary order is presented. The basis is formed by Taylor series expansions of the stresses with respect to the strains, which in turn are expanded towards the spatial directions. With a split of the material and geometric nonlinearities and the assumption of a material behavior linearly variable within an element, the strain energy in elements of arbitrary shape and polynomial order can be evaluated exactly. Therefore, geometric moments have to be calculated in preprocessing, requiring only evaluations of derivatives at a single integration point during the analysis. The moments can be effectively integrated analytically over the boundary of the elements. As one of the manifold applications, the use in the context of second order virtual elements is elaborated for which the assembly time can be significantly reduced. The combination with the automatic differentiation and expression optimization software AceGen provides performant element routines. In the numerical examples, the integration scheme shows promising accuracy and makes the application in more complex material models up to computational homogenization attractive.

Poka Yoke in Smart Production Systems with Pick-to-Light Implementation to Increase Efficiency

Product assembly is often the last step in the manufacturing process. This task is usually performed by an assembly worker who needs to have practical experience and expertise. For complex products, the assembly may require a long time to study assembly plans. This paper presents a custom-designed Pick-to-Light system using Poka Yoke principles to make this activity easier. The created modular system with two-stage verification serves to guide the assembler precisely. It shows him on the display which parts he should use in a strictly defined assembly step. Our proposal aims to shorten assembly time and reduce the number of errors, which was supported by a case study in a small company with 30 employees. After analysing the data, we can declare that the proposed system significantly reduces the time required for assembly from 7 to 35% and reduces the error rate by 35%. The solution is scalable and flexible, as it can be easily adapted to display assembly steps for a different product.

Metachronous colorectal cancer risk according to Lynch syndrome pathogenic variant after extensive versus partial colectomy in the Netherlands: a retrospective cohort study

Extensive colectomy (subtotal or total colectomy) is often advised for carriers of Lynch syndrome with colorectal cancer. However, the risk of metachronous colorectal cancer might differ by Lynch syndrome variant, meaning that partial colectomy, which has better functional outcomes, might be adequate for some patients with low-risk variants. We aimed to assess the risk of metachronous colorectal cancer after partial colectomy and extensive colectomy in carriers of Lynch syndrome with different pathogenic variants. For this retrospective cohort study, carriers of Lynch syndrome with colorectal cancer in the Netherlands were identified by linkage of the Dutch Foundation for the Detection of Hereditary Tumors (StOET) database and the Dutch Nationwide Network and Registry of Histopathology and Cytopathology (PALGA) database. Data on demographics, Lynch syndrome variants, colorectal cancers, surgery types, mortality, and surveillance colonoscopies were extracted. Data on colorectal cancer and surveillance colonoscopies were updated until Feb 28, 2022. Data on survival status was updated until Feb 7, 2022. MLH1, MSH2, and EPCAM were classified as high-risk variants and MSH6 and PMS2 as low-risk variants. Patients for whom the type of surgery was unknown were excluded. Cox regression time-to-event analyses were done to assess the risk of metachronous colorectal cancer in four subgroups based on pathogenic variant (high-risk vs low-risk variants) and the extent of surgery (extensive colectomy vs partial colectomy). Sex, age at the time of primary colorectal cancer, primary colorectal cancer stage, performance of surveillance colonoscopies, adherence to the surveillance guidelines, and time period of primary colorectal cancer diagnosis were added to the model as possible confounders. Metachronous colorectal cancer was defined as colorectal cancer diagnosed more than 6 months after the primary colorectal cancer. Patients were censored at time of death or assembly of the database. Of 1908 carriers of Lynch syndrome registered in StOET, 532 with a history of colorectal cancer were identified after linkage with PALGA. Five carriers were excluded because of an unknown surgery type, leaving 527 in our sample (mean age at primary colorectal cancer 48·7 years [SD 12·1]; 274 [52%] male and 253 [48%] female). 121 (23%) patients developed metachronous colorectal cancer (median time from primary colorectal cancer to metachronous colorectal cancer 11·0 years [IQR 2·1-17·8]). Metachronous colorectal cancer occurred in 12 (12%) of 97 patients with high-risk variants and extensive colectomy, in 85 (32%) of 267 patients with high-risk variants and partial colectomy, in zero (0%) of 11 patients with low-risk variants and extensive colectomy, and in 24 (16%) of 152 patients with low-risk variants and partial colectomy. Partial colectomy was associated with a higher risk of metachronous colorectal cancer than extensive colectomy in the high-risk variant group (hazard ratio 1·97, 95% CI 1·04-3·73; p=0·039). The risk of metachronous colorectal cancer did not differ between carriers of low-risk variants who had partial colectomy and those of high-risk variants who had extensive colectomy (1·14, 0·55-2·36; p=0·72). The risk of metachronous colorectal cancer after partial colectomy in carriers of low-risk variants is similar to the risk after extensive colectomy in carriers of high-risk variants. This finding suggests that partial colectomy followed by endoscopic surveillance is an appropriate management approach to treat colorectal cancer in carriers of low-risk Lynch syndrome variants. None.

PTHP: Index for Optimizing Genome Assembly Overlapping and Read Alignment

Unfortunately, sequencing technology can only access the genome sequence as massive numbers of short strings are called reads. The genome assembly process constructs the complete genome from these reads based on the overlapping between the reads, called the de novo approach, or aligns the reads based on their positions in the available reference genome, called the reference-guided approach. Millions of reads search for overlapping or alignment, a well-known data structure problem called all-against-all. Many studies have proposed indexing such as hash index, prefix tree index, and parallelization technique to optimize the overlapping or the read alignment individually. However, due to the massive data amount and the repeats, limitations still affect the index efficiency, requiring more enhancements. This article introduces a new hybrid index named Prefix Tree Hash Partitioned index(PTHP), which combines prefix-tree index, hash index, pigeonhole concept, and parallelization. PTHP index reveals significant results on the simulation and real dataset, reducing the computational time complexity of overlapping and read alignment, thus the assembly time outperforming prefix tree index and hash index. Improving the performance of overlapping and read alignment using the PTHP index reveals great results in optimizing the hybrid genome assembly that combines both.

Audio-Visual Effects of a Collaborative Robot on Worker Efficiency

Collaborative workplaces are increasingly used in production systems. The possibility of direct collaboration between robots and humans brings many advantages, as it allows the simultaneous use of human and robotic strengths. However, collaboration between a collaborative robot and a human raises concerns about the safety of the interaction, the impact of the robot on human health, human efficiency, etc. Additionally, research is unexplored in the field of the collaborative robot’s audio-visual effects on the worker’s efficiency. Our study results contribute to the field of studying collaborative robots’ audio-visual effects on the worker’s behavior. In this research, we analyze the effect of the changing motion parameters of the collaborative robot (speed and acceleration) on the efficiency of the worker and, consequently, on the production process. Based on the experimental results, we were able to confirm the impact of robot speed and acceleration on the worker’s efficiency in terms of assembly time. We also concluded that the sound level and presence of a visual barrier between the worker and robot by themselves have no effect on the worker’s efficiency. The experimental part of the paper clearly identifies the impact of visualization on work efficiency. According to the results, the robot’s audio-visual effects play a key role in achieving high efficiency and, consequently, justifying the implementation of a collaborative workplace.

Fabrication of Flexible and Transparent Metal Mesh Electrodes Using Surface Energy-Directed Assembly Process for Touch Screen Panels and Heaters.

Transparent conductive electrodes (TCEs) are indispensable components of various optoelectronic devices such as displays, touch screen panels, solar cells, and smart windows. To date, the fabrication processes for metal mesh-based TCEs are either costly or having limited resolution and throughput. Here, a two-step surface energy-directed assembly (SEDA) process to efficiently fabricate high resolution silver meshes is introduced. The two-step SEDA process turns from assembly on a functionalized substrate with hydrophilic mesh patterns into assembly on a functionalized substrate with stripe patterns. During the SEDA process, a three-phase contact line pins on the hydrophilic pattern regions while recedes on the hydrophobic non-pattern regions, ensuring that the assembly process can be achieved with excellent selectivity. The necessity of using the two-step SEDA process rather than a one-step SEDA process is demonstrated by both experimental results and theoretical analysis. Utilizing the two-step SEDA process, silver meshes with a line width down to 2µm are assembled on both rigid and flexible substrates. The thickness of the silver meshes can be tuned by varying the withdraw speed and the assembly times. The assembled silver meshes exhibit excellent optoelectronic properties (sheet resistance of 1.79Ω/□, optical transmittance of ≈92%, and a FoM value of 2465) as well as excellent mechanical stability. The applications of the assembled silver meshes in touch screen panels and thermal heaters are demonstrated, implying the potential of using the two-step SEDA process for the fabrication of TCEs for optoelectronic applications.

Optimization of Bolted Joints: A Literature Review

Bolted joints are widely used in the aerospace and automotive industries due to their ease of assembly, disassembly and design flexibility. Optimizing threaded fasteners is essential to achieve uniform load distribution and minimize the number of bolts required, thereby reducing system cost and weight. This review paper aims at summarizing the five optimization techniques available in the literature, including bolt layout, tightening strategies, tightening sequences, bolt size, and stresses. The purpose is to emphasize the importance of optimizing bolted joints via the proper selection of materials, geometry, patterns, and bolt sizes, to obtain efficient joints with low assembly time while maintaining strength.

The MISLI-Drive, a modular sterilizable robotic driver for steerable laparoscopic instruments.

Introduction: Based on the success of the former "Shaft-Actuated, Tip-Articulated" SATA-Drive, a prototype robotic instrument driver for modular, steerable, laparoscopic instruments, a new driver is designed and tested to improve previously lacking features concerning cleanability, instrument adaptation, practical application and control. The design of the driver engages these issues with a modular design aimed at re-use of both the instrument and the driver, for which a set of design requirements are established. Methods: A new modular design has been developed to improve cleanability through separation of the electro-motors and the instrument mechanism which clutches the instrument. Contamination of the driver's robotic side is prevented though a combination of a drape and a Sterile barrier interface, while the instrument side is made sterilizable. A novel instrument clutching mechanism enables quick-release features, while a motor-axis latching mechanism enables plug-and-play assembly. Embedded sensors allow precise and fast control. A user-experiment was conducted on instrument exchange and assembly time, while mechanical and electrical tests were conducted on the driver's responsiveness. Results: The driver has proven its ability to control the instrument, after which it can be disassembled for cleaning and inspection. The driver is designed for re-use through disassembled sterilization where all possibly contaminated surfaces are exposable for cleaning and inspection. The new standardized instrument clutches allow easy instrument (dis-)assembly. Instrument exchange is possible in two methods, the fastest of which is a median of 11 (6.3-14.6) seconds. The driver's instrument mechanism is separated in a median of 3.7 (1.8-8.1) seconds. After assembly, the driver is operational in less than 2 s. Discussion: Instrument exchange times are similar to the semi-reusable Da Vinci systems, yet the MISLI-Drive is designed for sterilization, inspection and continual re-use. The modular build of the driver also allows easier parts replacement during maintenance, and requires minimal adaptation to different future scenarios, which is expected to reduce the overall cost of use.

DATA ENGINEERING IN CRISP-DM PROCESS PRODUCTION DATA – CASE STUDY

The paper describes one of the methods of data acquisition in data mining models used to support decision-making. The study presents the possibilities of data collection using the phases of the CRISP-DM model for an organization and presents the possibility of adapting the model for analysis and management in the decisionmaking process. The first three phases of implementing the CRISP-DM model are described using data from an enterprise with small batch production as an example. The paper presents the CRISP-DM based model for data mining in the process of predicting assembly cycle time. The developed solution has been evaluated using real industrial data and will be a part of methodology that allows to estimate the assembly time of a finished product at the quotation stage, i.e., without the detailed technology of the product being known.

Real-time path planning based on improved artificial potential field method

Nowadays, with the development of robotics-related technology, its applications permeate many aspects of work and life; In product manufacturing and assembly, tech companies switch from manual to robot automation which improves the production volume and reduces the assembly time. In the tertiary sector including health and social work, the robots learn how to interact with people to meet specified requirements. Path planning constitutes a critical module of robotics engineering that aims to provide the optimal solution for the robot to reach its target point. The artificial potential field methods, refers to APF, are widely used to realize path planning due to their simplicity of calculation and effectiveness in obstacle avoidance. However, the traditional artificial potential field method features the local minimum and oscillation, and unreachable target point problems that make it hard for robots to reach the target point. Based on the weaknesses, an improved version of the gravitation and repulsion force function was introduced in this paper. In addition, the concept of safety distance also contributed to the path planning for robots. Through the simulation experiment, it was shown that the improved APF algorithm successfully addressed the local minima and unreachable target point problem, which could navigate robots to arrive at the destination in both 2D and 3D space by avoiding collision with obstacles.

Using the old-growth concept to identify old species-rich semi-natural grasslands

The concept of ‘old growth’, originally developed for forests, was recently extended to grassland to distinguish old natural grasslands (NG) from semi-natural grassland (SNG). Comparing mesophile SNGs of different ages, we show that the concept is also able to distinguish old SNGs from young SNGs and also that assembly time plays a determining role in the ecology and evolution of SNG. As expected from the old-growth concept and like NG, old SNGs have an unique floristic composition with a higher greater proportion of long-lived species with underground storage, clonal growth organs and bud banks, higher species richness, diversity and evenness. Furthermore, they have much greater floral abundances and contain sedge species not found in younger SNGs such as Carex caryophyllea which is a reliable indicator of old unimproved species-rich grasslands. Comparison with other old grassland systems suggests that the old SNGs are probably remnants of the rich biodiversity of the grassland vegetation that was once widespread in the Atlantic biogeographic region. Given their ecological, cultural and aesthetic values and their role in essential ecosystem services, these threatened old SNGs deserve urgent protection.

A Discrete Cooperative Control Method for Production Scheduling Problem of Assembly Manufacturing System

With a sharp decrease in resource utilization of the complex production process, integrated scheduling methods are urgently needed in assembly manufacturing industries. To this end, this paper presents an integrated scheduling with jobs processing and assembly sequence (ISJPAS) problem where jobs and assemblies can be processed simultaneously. As the first contribution to this work, we develop a mixed integer nonlinear programming model (MINLP) that aims at minimizing maximum completion time and determining the earliness and tardiness of jobs and resulting inventory time. The structured property of the optimal scheduling solution is analyzed with regard to job sequencing and assembly sequencing. The NP-hard nature of the problem is proved, which provides upper and lower bounds on the optimal solution. Second, an efficient discrete assembly time and arrival time control (DAATC) method is presented based on continuous time variable control models. From a modified set of benchmark problems, the proposed method is tested by comparing four assembly association levels in real applications. The comparisons indicate the potentiality of our method to satisfy the due date. Lastly, relevance of practical applications are discussed, and several future research avenues are emphasized.

Development and Verification of a Simulation Model of an Automated Assembly Line

Simulation models are integral to IT solutions built according to the Industry 4.0 concept. They are often the basis for developing digital twin solutions, which is why development environments are constantly developed and improved to meet the growing requirements of manufacturing enterprises. This work presents the development and verification of a simulation model of an automated assembly line located in the Smart Factory laboratory of the Poznań University of Technology. One of the criteria for designing the assembly process on this line is the time it takes for transport pallets to pass through individual stations. The work is a response to the need to quickly analyze the designed product assembly scenarios to choose the best one. The operation of the automated line with six assembly stations and allowing for the simultaneous transport of six pallets were considered. The main purpose of the work was to build a simulation model that would allow us to obtain assembly times close to real. The model was created using the Tecnomatix Plant Simulation 16.0 software, and verification work was carried out through a comparative analysis of the results of the simulation time of various assembly scenarios in relation to the actual operation of the line.