Dimensional Requirements Research Articles

Factor Influencing the Generosity Behaviour of Cash Waqf Donors in Malaysia: A Mediation Model using Structural Equation Modelling Approach

This present study employs the structural equation modelling (SEM) approach to investigate the influence of philanthropic attitude (PA), subjective norms (SN), perceived behavioural control (PBC) and Islamic Humanitarianism (IH) on the generosity behaviour of cash Waqf donors (CWGB) in Malaysia. Additionally, this study also examined the role of generosity behavioural intention (GBI) as a mediator in the relationship between PA, SN, PBC and IH towards cash Waqf generosity behaviour. This resulted in a total of nine hypotheses for the study. The model was constructed by integrating the theory of planned behaviour (TPB), the theory of Islamic consumer behaviour (TICB) and the theory of welfare policy and support (TWPS). The survey was conducted randomly among 375 respondents in Technical and Vocational Education and Training (TVET) institutions in Malaysia, with 372 valid cases. The selection of academia was influenced by their diverse educational backgrounds, as prior behavioural studies have demonstrated the significance of education in various contexts. This research used a close-ended structured questionnaire to assess all the constructs involved in this study. The questionnaire was adapted from previous research using a 10-point interval rating scale to collect responses from the respondents. Pooled Confirmatory Factor Analysis (CFA) is employed to validate measurement model in this study. All constructs have achieved uni- dimensionality, validity and reliability requirement. The study’s findings indicate that 59% of the performance in cash Waqf generosity behaviour can be explained by the constructs PA, SN, PBC, IH, and GBI within the model. Remarkably, PA, IH and GBI demonstrate a positive and significant influence on the generosity behaviour of cash Waqf donors. While SN demonstrate a negative and significant influence on the generosity behaviour of cash Waqf donors. Nonetheless, the construct of PBC does not significantly influence the generosity of cash Waqf donors. Interestingly finding of mediation analysis revealed that GBI mediate the relationship between PA and SN (partial mediation), PBC and IH (full mediation) toward generosity behaviour among cash Waqf donors. This study presents a novel concept by defining the construct of generous behaviour to investigate the factors that affect this behaviour through SEM. This study focuses exclusively on generosity-related behaviours, particularly monetary donations in the form of cash Waqf. Future research may evaluate generosity behaviour by investigating two additional cross-cultural human behaviours: assisting strangers and dedicating time to volunteer for an organization.

Bright, circularly polarized black-body radiation from twisted nanocarbon filaments.

Planck's law ignores but does not prohibit black-body radiation (BBR) from being circularly polarized. BBR from nanostructured filaments with twisted geometry from nanocarbon or metal has strong ellipticity from 500 to 3000 nanometers. The submicrometer-scale chirality of these filaments satisfies the dimensionality requirements imposed by fluctuation-dissipation theorem and requires symmetry breaking in absorptivity and emissivity according to Kirchhoff's law. The resulting BBR shows emission anisotropy and brightness exceeding those of conventional chiral photon emitters by factors of 10 to 100. The helical structure of these filaments enables precise spectral tuning of the chiral emission, which can be modeled using electromagnetic principles and chirality metrics. Encapsulating nanocarbon filaments in refractive ceramics produces highly efficient, adjustable, and durable chiral emitters capable of functioning at extreme temperatures previously considered unattainable.

Static and dynamic analyses and multi-objective optimization of wafer thinning machine’s design variables

In order to meeting the physical strength, heat dissipation and dimensional requirements of chips, the wafer surface needs to be thinned by wafer thinning machines. In the design of wafer thinning machine, the analysis and optimization of castings is an important and complex issue. In this study, the multi-objective optimization of wafer thinning machine’ s design variables are executed due to static and dynamic analyses. According to the analysis results, the design quality, amplitude and equivalent stress of the casting are optimized. The inner diameter of the ring, the height of the ring, the height of the middle groove, and the height of the groove on both sides are selected as the main design variables of the optimization. The results show that the static deformation of the optimized cast structure is 8% lower than the original structure, the overall mass is 4% lower, the operating frequency is 3.5% lower, higher stability, smaller mass and amplitude are obtained after optimization. The research has a great significance for the wafer thinning machines design, and provides theoretical guidance for the development of other lithography equipments.

Stem recovery and harvesting productivity of two different harvesting systems in final felling of Pinus patula

ABSTRACT With the current demand of wood products and industrial requirements, plantation owners need to re-think ways in which harvesting is carried out and identify the most efficient harvesting system that also utilizes small diameter parts of stem per industry’s product specifications. This paper contributes to the discussion by comparing the harvesting productivity and stem recovery between conventional harvesting (CH) and integrated harvesting (IH) systems. CH is harvesting which does not necessarily align with the log dimensional requirements of the customer and only recovers logs with big diameters while IH is based on harvesting and sorting logs according to need in a single operation so that as much volume and value as possible of the stands is realized. The study was carried out at the Sao Hill Forest Plantation in the Southern Highlands of Tanzania. The harvested compartment was purposively selected and divided into IH and CH plots. A total of 39 trees were randomly selected to be harvested from each plot. The findings portray a significant difference in the stem recovery of 75% for IH and 60% for CH. CH had an average cutting productivity of 16 m3/h as compared to 14 m3/h for IH while skidding productivity was 15.3 m3/h and 24.9 m3/h for IH and CH, respectively. In this study, the IH system resulted in higher production in terms of volume recovered, meaning IH had a significant impact on the production and stem recovery of the standard stem-wood for use in different industries.

A clean, simple, and efficient method for preparing vibration-reducing low-carbon bamboo building materials with high strength

Large-format bamboo panels prepared by bamboo flattening are adhesive-free and retain the natural structure of bamboo, making them ideal materials for interior architecture. However, due to poor dimensional stability and vibration-reducing properties, flattened bamboo easily deforms and vibrates when applied to building walls and floors due to ambient humidity changes or external excitation, impacting both comfort and structural safety. In this work, a clean, efficient, and simple densification process for flattened bamboo is developed to prepare low-carbon bamboo building materials with enhanced vibration reduction. The results indicated that the densification process reduced the vibration intensity of the flattened bamboo under excitation, changed its vibrational modes, avoided low-frequency resonance, and improved its vibration reduction and suppression properties. The dynamic stiffness of the densified bamboo increased to 3.23–3.63 times, while the root mean square (RMS) and transfer function value decreased by 20.84 % and 62.5 %, respectively. The MOE (16.2 GPa) and MOR (276 MPa) increased to 2.73 times and 2.22 times, respectively. The densified bamboo met the dimensional stability requirements of the GB/T 18102–2020 building material standards. Compared with damping, the increased stiffness played the primary role in improving the vibration-reducing properties of densified bamboo. The hydrothermal mechanical treatment changed the structure and composition. From a macroscopic perspective, the gradient structure of the vascular bundles and parenchyma cells was gradually plasticized and homogenized, compacting large capillary pores and channels such as those in parenchyma cells, vessels, and sieve tubes. On a microscopic level, defects such as pits, intercellular spaces, and micropores were filled, and microfibrils between the middle lamellae were tightly stacked, forming a mechanically-interlocked structure. At the molecular scale, there was an increase in the crystallinity and orientation of cellulose molecular chains, accompanied by an increase in hydrogen bond density. The densified bamboo developed in this study shows good application potential for vibration-reduction structures such as buildings and rail transit.

On the Fundamentals of Reverse Ring Rolling: A Numerical Proof of Concept.

Ring Rolling is a near-net manufacturing process with some measurable dimensional inaccuracies in its products. This fact is exaggerated even more under the scope of high-precision manufacturing, where these imprecisions render such products unfitting for the strict dimensional requirements of high-precision applications (e.g., bearings, casings for turbojets, etc.). In order to remedy some of the dimensional inaccuracies of Ring Rolling, the novel approach of Reverse Ring Rolling is proposed and investigated in the current analysis. The conducted research was based on a numerical simulation of a flat Ring Rolling process, previously presented by the authors. Since the final dimensions of the ring from the authors' previous work diverged from those initially expected, the simulation of a subsequent Reverse Ring Rolling process was performed to reach the target dimensions. The calculated deformational results revealed a great agreement in at least two of the three crucial dimensions. Additionally, the evaluation of the calculated stress, strain, temperature and load results revealed key aspects of the mechanisms that occur during the proposed process. Overall, it was concluded that Reverse Ring Rolling can effectively function as a corrective process, which can increase the dimensional accuracy of a seamless ring product with little additional post-processing and cost.

Multiangle perception-oriented environmental facility design method based on joint fuzzy decision-making and transfer learning.

In modern society, the demand for environmental facilities is increasing, and how to effectively design and plan environmental facilities has become an urgent issue. However, traditional design methods often consider only certain requirements and perspectives, resulting in design results deviating from the expectations of actual users. In this study, first, perceptual fuzzy decision-making and design transfer learning were selected as methods. Second, by applying multiple perspectives to environmental facility design methods, these two methods were combined, and a new joint algorithm was proposed. Third, when designing environmental facilities, a joint processing framework was constructed considering the impact of human factors, environmental parameters, and cultural value parameters on the design results. Last, the proposed joint algorithm was validated for functionality and satisfaction. The experimental results of this article indicate that in temperature control design, the accuracy of this research model is 17.7-19.6% greater than that of traditional centralized algorithms. In terms of lighting design, the model results of this study are good, with an increase of 16.7-20.2%. This method comprehensively considers the various dimensional requirements of environmental facilities and has good migration performance. In future studies, we will further investigate the applicability of this method in different scenarios and applications to promote the further development of environmental design.

Design, Modeling, and Control of a Compact and Reconfigurable Variable Stiffness Actuator Using Disc Spring

Abstract This paper proposes a compact and reconfigurable variable stiffness actuator (VSA) using disc spring which is named as SDS-VSA (symmetrical disc spring variable stiffness actuator). To enhance the actuator’s torque density, symmetric compression springs are integrated into the cam-roller-spring mechanism, and a disc spring combination design is employed instead of conventional springs. The disc spring configuration is tailored to achieve a broader stiffness range within a limited size, aligned with stiffness and dimensional requirements. Subsequently, the dynamics of the cam-roller-spring mechanism are derived. To tackle the challenge of strong coupling dynamics, a decoupled modeling method by introducing mismatched and matched disturbances is proposed. A back-stepping tracking controller and proportional-derivative (PD) controller with feedforward are proposed to track the link-side and stiffness motor-side trajectories, respectively. Tracking experiments under significant stiffness alteration are conduced to verify the performance of the prototype SDS-VSA.

Abstract A007: Picturing progression: A new role of whole slide imaging in comprehensive clinical genomic datasets

Abstract Introduction: Real world data is needed to understand cancer evolution based on changing standards of care. While Next Generation Sequencing (NGS) is the preferred standard for confirmatory testing of mutational status, its use varies tremendously across settings and countries, with the most influential variable being cost. In this research, we examined the utility of Whole Slide Images (WSI) as a discrete data type to predict mutational and other statuses to inform assessments of clinical progression. This could include initial mutational status or the evolution of resistance to a specific treatment and the emergence of a new driver mutation. Experimental Procedures: We have curated datasets from 4000 NSCLC and 2000 CRC patients with clinically tested WES, WTS and WSI tumors with deeply curated longitudinal clinical electronic medical records were compiled through a partnership between ConcertAI and Caris Life Science. This de-identified clinical dataset is drawn from a diverse range of U.S. community and academic oncology practices. The practice patterns reflect the real-world variability of treatment and utilization of molecular testing. Additional stratification was performed based on lines of therapy and evidence of clinical progression for patients with information available. Results: Features from whole slide H&E images were extracted and compared between subcohorts of interest. We demonstrated the correlation of the WSI features with TMB, MSI-H, molecular variants, differential gene expression and PD-L1 IHC of these cohorts within the context human interpretable features (HIFs) of whole slide images. Conclusion: The availability of whole slide images (WSI) is a dimensionality requirement for real world longitudinal comprehensive clinical datasets. Digital images should be considered as a key deliverable of clinical genomic datasets and have the potential to inform treatment selection and outcomes. In settings where NGS is not the standard of care, WSI could be used to predict the value of a test for treatment decisions or determination of prospective clinical trial eligibility. Where the cost of NGS is fundamentally prohibitive, such as less developed economies, WSI is a much lower cost modality that could have very high utility in guiding treatment decisions with better predicted outcomes. In all cases WSI imaging could be used to assess potential status or acquired resistance and the evolution of a new driver mutation. All critical in the decision to continue or discontinue a specific treatment. Citation Format: Elizabeth G. Sweeney, Yawei J. Wang, Jacob Picard, Jim Abraham, Eghbal Amidi, Michael R. Rossi, Sergey Klimov, Claudio D'Ambrosio, Ming Chen, Jeff Elton, George Sledge. Picturing progression: A new role of whole slide imaging in comprehensive clinical genomic datasets [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr A007.

Measurement method of hot forging dimension based on green laser depth information.

The application field of large forgings is extensive. Accurate dimensional measurement is an important factor to ensure the quality of the finished forging product when it is forged at high temperature. Therefore, this paper proposes a green laser scanning measurement method based on depth information. First, a geometric measurement model based on depth information is established by studying the relationship between green laser depth information and forging dimension. Then, based on the heat transfer theory, distribution of the temperature field around hot forgings is studied, and an error function caused by light refraction is established using a ray tracing algorithm. After that, the error function is used to modify the measurement model to obtain the accurate distance between the forging and background plane and then obtain the dimensional information of the forging. Finally, this measurement method was experimentally verified in the laboratory, and the experimental results show that the measurement error of this method meets the dimensional measurement requirements of large hot forgings.

New perspectives in the treatment of the severe atrophic posterior maxilla: interpositional sandwich osteotomy combined with sinus floor grafting - a novel technique

Purpose: Dental implant installation in the posterior maxilla depends fundamentally on the presence of an adequate bone quantity. Tooth loss in the posterior maxilla is followed by extensive loss of the alveolar ridge and increased maxillary sinus pneumatization that often makes implant installation difficult to achieve. Maxillary sinus floor augmentation is traditionally the common surgical technique to overcome this situation. When the deficiency in the vertical dimension relates more to severe ridge resorption, crestal ridge augmentation should also be considered. Posterior maxillary sandwich osteotomy combined with sinus augmentation, using inter–positional bone graft might be a viable option to address this problem. This study describes a successful implementation of this technique to solve a severe vertical osseous ridge defect under the sinus floor. Material and Methods: A two–stage lateral wall sinus floor augmentation combined with inter–positional sandwich osteotomy followed by the insertion of dental implants with adequate length and diameter was performed. Deproteinized natural bovine bone mineral (DBBM) covered by a resorbable collagen membrane were used. Rehabilitation of this area was completed by a standard prosthetic protocol. Results: As a result of completing the above procedure favourable bone mass and form was created to enable implant placement in positions that are optimal from a prosthetic and esthetic point of view in terms of reshaping the alveolar crest and normali- zing the interocclusal distance improving the crown–implant ratio. Conclusion: This case demonstrates a step–by–step illustration of an innovative technique for overcoming a vertical ridge defect combined with increased maxillary sinus pneumatization. It can be concluded that this novel technique is recommended to meet the dimensional requirements of bone augmentation both crestal and intrasinusal in severe atrophic posterior maxilla to achieve an improved alveolar plane, equalized crown–to–implant ratios, and a more favourable gingival shape.

Single point machining of A205 aluminum: A comparison of cast and additively manufactured materials

A205 aluminum is an additively manufacturable alloy that was recently approved for aerospace use. To date, research has focused on finding proper heat treatments and their resulting material properties, but there is a distinct lack of research on how to properly post-process printed parts to meet dimensional requirements. Machining is a commonly used post-processing procedure. This study compares the machinability of cast and additively manufactured (AM) A205 aluminum to find common pitfalls and strategies to overcome them. Here, machinability is determined by the final surface roughness and finish, as well as specific cutting energy and vibrations. These results are explained by microstructural analyses. The study finds that AM A205 aluminum has slightly better machinability than as cast thanks to its clear, consistent tooling marks at a lower speed. This is attributed to the AM sample's higher hardness, 122.5 HV vs. 90.0 HV, and lower ductility because of the small grains and even distributed TiB2 and α-Al solid solution. Overall, the results show that A205 is machinable and that increasing the cutting speed generally improves the surface finish.

FOUR-COMPONENT ZOOM-AFOCAL SYSTEMS ZOOM-TRANSFOCACATORS OF THREAD RANGE METERS

The problem addressed in this research is the parametric synthesis of zoom-afocal optical systems for transfocusors used in measurement technology, specifically thread-type rangefinders. The research aims to develop a universal analytical algorithm that can be computerized for calculating the optical and dimensional parameters of four-component zoom-afocal lens systems for trans-focusors.The implementation methodology involves representing the zoom-afocal system as a sequence of thin components.Using a system of equations where the optical powers of the components and the distances between them are unknown, the values of these parameters are determined to achieve the desired range of angular magnification and zero optical power of the afocal system. The optical powers of the components and their ratios must ensure positive values for the distances between the components. The calculation of the light diameters of the components takes into account the permissible vignetting of the ray bundle from the field of view edge by determining the angles and heights of the zero rays on the system's components.The research results include analytical dependencies that enable the determination of component optical powers and their mutual arrangements throughout the entire range of angular magnification based on the input data. The research shows that the first component has the largest light diameter, which reaches its maximum value as the angular magnification approaches the maximum within the specified range.The obtained results allow for the parametric synthesis of four-component zoom-afocal systems in an analytical form, considering the dimensional requirements, range of angular magnification, and permissible vignetting of ray bundles from the field of view.

Dry and Minimum Quantity Lubrication Machining of Additively Manufactured IN718 Produced via Laser Metal Deposition

Inconel 718 (IN718), a Ni-based superalloy, is immensely popular in the aerospace, nuclear, and chemical industries. In these industrial fields, IN718 parts fabricated using conventional and additive manufacturing routes require subsequent machining to meet the dimensional accuracy and surface quality requirements of practical applications. The machining of IN718 has been a prominent research topic for conventionally cast, wrought, and forged parts. However, very little attention has been given to the machinability of IN718 additively manufactured using laser metal deposition (LMD). This lack of research can lead to numerous issues derived from the assumption that the machining behavior corresponds to conventionally fabricated parts. To address this, our study comprehensively assesses the machinability of LMDed IN718 in dry and minimum quantity lubrication (MQL) cutting environments. Our main goal is to understand how LMD process variables and the cutting environment affect cutting forces, tool wear, surface quality, and energy consumption when working with LMDed IN718 walls. To achieve this, we deposited IN718 on SS309L substrates while varying the following LMD process parameters: laser power, powder feed rate, and scanning speed. The results unveil that machining the deposited wall closer to the substrate is significantly more difficult than away from the substrate, owing to the variance in hardness along the build direction. MQL greatly improves machining across all processing parameters regardless of the machining location along the build direction. Laser power is identified as the most influential parameter, along with the recommendation for a specific combination of power feed rate and scanning speed, providing practical guidelines for optimizing the machining process. While MQL positively impacts machinability, hourly energy consumption remains comparable to dry cutting. This work offers practical guidance for improving the machinability of LMDed IN718 walls and the successful adoption of LMD and the additive–subtractive machining chain. The outcomes of this work provide a significant and critical understanding of location-dependent machinability that can help develop targeted approaches to overcome machining difficulties associated with specific areas of the LMDed structure. The finding that MQL significantly improves machining across all processing parameters, particularly in the challenging bottom region, offers practical guidance for selecting optimal cutting conditions. The potential economic benefits of MQL in terms of tool longevity without a substantial increase in energy costs is also highlighted, which has implications for incorporating MQL in several advanced manufacturing processes.

Investigation of coatings with in-situ TiX reinforcements fabricated by additive-subtractive manufacturing: Hardness, microstructure and machinability

Wear resistance is essential for the long lifespan of critical components such as turbine blades in aircraft engines. Coatings reinforced by hard particles provide a highly effective means to enhance the anti-friction characteristics of these vital parts. Additive manufacturing presents a promising alternative for the fabrication of particle reinforced coatings. Nonetheless, it remains crucial to employ finishing processes on additively-manufactured parts to meet stringent quality and dimensional precision requirements before assembly. In this study, new findings on the additive-subtractive manufacturing of the coatings reinforced by in-situ TiC, TiB and TiB2 was comprehensively analyzed. The coupled influence of the fraction of WC and the laser power on the quality and properties of the coatings were explored, and the machinability of the coatings were evaluated via the finish milling. It was found that the fraction of WC was dominant on the morphology, phases, hardness, and microstructure of the laser-clad coatings; the difference in the properties of the coatings caused variance on the cutting force, surface quality and work hardening of the machined surface.

Ultrasonic Vibration-assisted Electrochemical Discharge Machining of Quartz Wafer Micro-Hole Arrays

The micro-hole machining of quartz wafers depends on photolithography techniques akin to those used in semiconductor fabrication. These methods present challenges due to high equipment setup costs, large space requirements, and environmental pollution risks. This research applies ultrasonic vibration assistance in electrochemical discharge machining to create an array of micro-holes on quartz wafers. In the experiments, a self-prepared tungsten carbide micro-electrode array served as the tool electrode. This electrode was a 2 × 2 square array, with needles measuring 30 × 30 μm. A series of experiments was conducted to investigate the effects of various machining parameters, including working voltage, feed rate, duration time, duty factor, and ultrasonic power level, on the characteristics of the micro-hole array. The characteristics included average hole diameter and through-hole surface morphology. The experimental objective was to achieve a through-hole diameter of 80 μm with an accuracy of ±8 μm. During the electrochemical discharge machining, suitable ultrasonic vibrations can thin the insulating gas film coating on the electrode surface, resulting in a more uniform gas film. As the insulating gas film’s thickness decreased, so did the critical voltage needed for the electrochemical discharge machining, reducing the hole’s diameter expansion. The ultrasonic vibration assistance can enable the satisfaction of the dimensional accuracy requirement. The experimental results indicate that ultrasonic vibration assistance can effectively improve the processing capacity and reduce sample fragmentation. A working voltage of 44 V, feed rate of 1 μm/6 s, duration time of 30 μs, duty factor of 30%, and ultrasonic power level of 1 resulted in better inlet and outlet surface morphology without outlet fragmentation. Moreover, the average diameters of the inlet and outlet were roughly 80 μm while meeting the through-hole diameter of 80 μm with accuracy of ±8 μm.

Structural thermal optical performance (STOP) analysis and experimental verification of an hyperspectral imager for the HYPSO CubeSat

The evaluation of space optical instruments under thermo-elastic loads is a complex and multidisciplinary process that requires integrating thermal, structural, and optical disciplines. This thorough analysis often requires substantial resources, leading small satellite projects to exclude it from their schedules. However, even though the instrument discussed in this paper is compact, its complex design and stringent dimensional stability requirements demand a comprehensive evaluation of its performance under thermal loads. The hyperspectral camera, which comprises 18 lenses, a grating, a slit, and a detector, is especially vulnerable to thermo-elastic distortions, as the deformation of even a single lens could significantly impact its performance. In this paper, we present the experimental validation of the STOP analysis applied to the HYPerspectral Small satellite for ocean Observation (HYPSO) Hypespectral Imager (HSI) model. Both the HSI Structural Thermal Optical Performance (STOP) numerical model and the HSI engineering model were subjected to identical thermal conditions in the simulations and in a Thermal and Vacuum Chamber (TVAC), and subsequently the optical results derived from simulations and the test campaign compared. To characterize the thermal field, an infrared camera and thermocouples were used. Moreover, to assess the thermal performance of the HSI, we measured the Full Width at Half Maximum (FWHM) of the main peaks in the intensity-wavelength spectra when the hyperspectral camera targeted a known spectral lamp. After individually calibrating the STOP models so that the FWHM and index of the intensity peaks are in close alignment with the experimentally measured FWHM and index, the lenses most sensitive for displacements were characterized.

Linking e-leadership to innovative and proactive work behaviors in tourism higher education institutions: a moderated mediation model using SEM

E-leaders should encourage academics to manage their multi- dimensional work requirements and even to go beyond these requirements to innovate in their tasks and achieve sustainable development in educational institutions. This study aims to examine the relationship between e-leadership, innovative work behavior and proactive work behavior in the presence of work engagement as a mediator. Researchers implemented a quantitative methodology. This study used data from an online survey of 398 academics in Egyptian tourism higher education institutions. The results of structural equation modeling presented strong support for the proposed model. E- leadership has been proven to affect innovative and proactive work behavior among academic staff positively. Work engagement has shown an effective and significant mediating role between the examined variables. Further, the academic department was proven to moderate the relation between e-leadership and innovative work behavior, while age had no moderation effect in this relation. The study draws researchers’ attention to the role of e-leadership in helping academics to cope with the dynamic nature of research and education.

The Research For Quickly Measuring The Diameter And Roundness Of Solder Balls Based On Machine Vision Technology

Abstract Solder balls used in electronic packaging should have high dimensional and shape accuracy requirements to ensure the connection quality of solder balls during soldering. However, the existing solder ball detection methods were hard to measure the diameter and roundness in an integrated and fast manner. Therefore, a new method and device for measuring the diameter and roundness of solder balls was proposed based on machine vision technology, including detection device and software design. The experimental device could detect the parameters of at least 40 solder balls at a time. The solder ball image was preprocessed in the software system to improve the quality of the solder ball image, and then the Harris operator successfully detected the concave point on the bonded solder ball image and realized the solder ball separation based on the shortest path matching criterion. Compared with the SEM measurement value, the diameter and roundness of solder balls measured by the detection system were smaller than 3%.

Numerical and experimental studies on design of multi-lumen tube extruded with drawing and air flow

This study represents the design and optimization procedure of a multi-lumen tube used for endoscopic retrograde cholangiopancreatography (ERCP) catheter. The geometry of tip and die for the multi-lumen tube is designed based on numerical analysis of molten polymer and air flow. In particular, this numerical study consider the interaction between the molten polymer and the air flow in the lumen which is the main process variable of extrusion, and analyze the heat transfer and pressure distribution through the air flow for the first time. In addition, to reflect the reality of the multi-lumen extrusion process, the velocity is controlled at the end of the tube ejected to the free surface in consideration of the extrusion process, which is drawn by the puller downstream of the extruder. The shear rate and temperature dependent viscosity of PEBAX 7233 SA01 MED is measured for non-isothermal numerical simulations. The extrusion process for multi-lumen tubes with drawing is simulated using ANSYS Polyflow. The profile of extrudate is numerically predicted with the initial design of the tip and die with the manufacturing parameter is optimized. The predicted profile of extrudate is compared to the target profile with dimensional requirements. The design of the tip and die is modified based on numerical results following the design procedure. To suppress the die swell phenomena, the flow area of molten polymer is increased, and the velocity difference is reduced. Finally, the multi-lumen tube with the optimized tip and die is experimentally extruded and compared to the target profile of the extrudate. It has a good agreement with the target profile and satisfies the dimensional requirements. This design procedure and numerical analysis help achieve the desired target profile of extrudate.