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This paper suggests a new method for determining the sewing damage that occurs in single jersey fabrics based on the calculation of the needle hole area. This paper also aims to investigate the effects of material type, sewing parameters, and repeated washing cycles on sewing damage by using this method.

Six knitted fabrics, differing in structure and raw material, were produced. Samples were sewn using different sewing parameters, and they were subjected to ten washing cycles. Values of average needle hole area, an objective indicator of sewing damage, were calculated before and after repeated washing cycles using image analysis software and were evaluated statistically.

The results showed that the average needle hole area calculated via the image analysis software effectively estimates sewing damage as the results obtained were compatible with those stated in the literature. Furthermore, fabric type, sewing direction, sewing thread type, and needle size significantly affected the sewing damage. However, stitch density did not affect the sewing damage. When the effect of washing cycles was compared, it was seen that washing leads to an increase in sewing damage.

A review of the existing literature shows that no previous study has evaluated sewing damage using image analysis software. This study proposes a novel objective method to determine the sewing damage that occurs in knitted fabrics.

Sewing is one of the most commonly used manufacturing processes in the world. Millions of parts are sewn every day ranging from cloths, shoes, furniture, to automobile seat covers. However, it is also one of the least understood processes. In fact, according to literature survey, few know how to calculate the sewing force or the fabric deformation during the sewing. This paper presents our research on using finite element model (FEM) to study the sewing process. The model is developed using ANSYS software system. In the model, the fabric is approximated by a number of perpendicular beam elements with elastic and plastic capabilities. On the other hand, the needle is modeled by a simple elastic beam. The contact between the two parts is modeled by contact elements. The variations of the needle geometry and the fabric material properties as well as the sewing conditions are also included in the model. The model can simulate the needle piercing through a material, and calculates the sewing forces as well as the fabric deformation forming a hole. It has been verified experimentally and can be used to study the effects of the key sewing parameters such as the fabric material properties and the needle geometry.

Selection of suitable sewing needle is one of the most important parameters for ensuring an effective and fault‐free sewing process. This task requires good knowledge of basic characteristics of a sewing needle, i.e. needle type, point shape and needle fineness. Also good knowledge of sewing materials is required. The contribution presents an analysis of important parameters that influence the sewing needle selection in women’s underwear production. The importance of those parameters in ensuring the appropriate seam quality is described. The selection of a suitable sewing needle was carried out on the basis of analysis of influential sewing parameters with application of machine learning from examples.

The present study aims to resolve the adjustment problem of cavitation bubble number density in simulations of the cavitating flows within the diesel injection nozzle holes using a two-fluid cavitation model.

The basic rule that determines the variations of cavitation bubble number density has been checked through the scaling analysis of a two-fluid model under the assumption of hydrodynamic similarity of the cavitating flows. Moreover, a phenomenological model for the number density of cavitation bubbles that takes the hydrodynamic effect into account has been developed through the combined analysis of cavitation bubble dynamics and internal flow characteristics of diesel injection nozzle holes. This new model has also been validated by the discharge coefficient measures in a wide range of injection conditions.

The values of cavitation bubble number density must rationally match changes both in liquid quality effect and in hydrodynamic effect corresponding to different cavitating flows. The validation results show that the two-fluid cavitation model together with this new cavitation bubble number density model predicts well both the cavitation content inside the diesel nozzle hole and the relationship between discharge coefficient and cavitation number, and the new cavitation bubble number density model has the potential to further expand the application range of the two-fluid cavitation model.

This study provides insight into hydrodynamic effect corresponding to cavitating flows inside diesel nozzle holes and presents an idea to model the cavitation bubble number density phenomenologically. The model idea and the developed model are useful to researchers and engineers in the area of nozzle internal flow and cavitating flow.

In electrochemotherapy, flexible electrodes, composed by an array of needles, are applied to human tissues to treat large surface tumors. The positioning of the needles in the tissue depends on the surface curvature. The parallel needle case is preferred, as their relative inclinations strongly affect the actual distribution of electric field. Nevertheless, in some case, small inclinations are unavoidable. The purpose of this paper is to study the electric field distribution for non-parallel needles.

The effect of electrode position is evaluated systematically by means of numerical models and experiments on phantoms for two different angles (5° and 30°) and compared with the case of parallel needles. Potato model was used as phantom, as this tissue becomes dark after few hours from electroporation. The electroporation degree was gauged from the color changings on the potatoes.

The distribution of electric field in different needle configuration is found by means of finite element analysis (FEA) and experiments on potatoes. The electric field level of inclined needles was compared with parallel needle case. In particular, the electric field distribution in the case of inclined needles could be very different with respect to the one in the case of parallel needles. The degree of enhancement for different inclinations is visualized by potato color intensity. The FEA suggested that the needle parallelism has to be maintained as possible as if the tips are closer to each other, the electric field intensity could be different with respect to the one in the case of parallel needles.

This paper analyzes the effect of inclined electrodes considering also the non-linearity of tissues.

The purpose of this paper was the design, development, and test of a flexible and reconfigurable experimental setup for the automatic manipulation of microcomponents, enhanced by an accurately developed vision-based control.

To achieve a flexible and reconfigurable system, an experimental setup based on 4 degrees of freedom robot and a two-camera vision system was designed. Vision-based strategies were adopted to suitably support the motion system in easily performing precise manipulation operations. A portable and flexible program, incorporating the machine vision module and the control module of the task operation, was developed. Non-conventional calibration strategies were also conceived for the complete calibration of the work-cell. The developed setup was tested and exploited in the execution of repetitive tests of the grasping and releasing of microcomponents, testing also different grasping and releasing strategies.

The system showed its ability in automatically manipulating microcomponents with two different types of vacuum grippers. The performed tests evaluated the success and precision of the part grasping and release, which is a crucial aspect of micromanipulation. The results confirm reliability in grasping and that the release is precluded by adhesive effects. Thus, different strategies were adopted to improve the efficiency in the release of stuck components without negatively affecting the accuracy nor the repeatability of the positioning.

This work provided a flexible and reconfigurable architecture devoted to the automatic manipulation of microcomponents, methodologies for the characterization of different vacuum microgrippers, and quantitative information about their performance, to date missing in literature.

Memories and musings of the long ago reveal revolutionary changes in the world's food trade and in particular, food sources and marketing in the United Kingdom. Earliest memories of the retail food trade are of many small shops; it used to be said that, given a good site, food would always sell well. There were multiples, but none of their stores differed from the pattern and some of the firms — Upton's, the International, were household names as they are now. Others, eg., the Maypole, and names that are lost to memory, have been absorbed in the many mergers of more recent times. Food production has changed even more dramatically; countries once major sources and massive exporters, have now become equally massive importers and completely new sources of food have developed. It all reflects the political changes, resulting from two World Wars, just as the British market reflects the shifts in world production.

This paper aims to provide a new drilling entry board for printed circuit board (PCB) process, superior in heat dissipation, lubrication, water solubility and hole location accuracy, achieving an excellent drilling process.

Using a mixture of polyethylene glycol (PEG) and water-soluble adhesives as hydrosoluble, endothermic and lubricant resins and aluminum foils as baseplates, a series of coated and aluminous entry boards (CABs) for PCB drilling was successfully prepared. The surface appearance of the entry boards was observed clearly by scanning electron microscopy (SEM). The endothermic and lubricant effects of the resins applied on the CABs was characterized by differential scanning calorimetry (DSC) and their water solubility was tested in the normal-temperature water (25°C). Moreover, the CABs’ good drilling properties were tested when they were used for PCB drilling.

The SEM analysis showed that the surfaces of the resin layers coated on the CABs whose coating thicknesses were less than 80 μm were smoother and flatter, which could improve hole location accuracy and reduce drill breakage ratio. By virtue of DSC, the endothermic and lubricant effects of the CABs were proven. The fusion of PEG in the resin layers could absorb the heat produced by drilling, restrain the temperature of the drill bit and hole rising and lubricate the drill bit efficiently when a hole was being drilled, which could achieve high-quality holes with good production efficiency. The water-soluble test showed that the prepared CABs had excellent water solubility at normal temperature, enabling the resin left on the hole walls and in the flute of the drill bit to be washed away easily and thereby improving the drilling efficiency and quality. The drilling tests showed that the increase in the thickness of the CABs’ coating could improve the hole location accuracy and alleviate the bit wear. In addition, the suitable coating thickness could ensure the firm adhering of the resin coating the aluminum foil, effectively avoid drill intertwist and prevent the resin debris from blocking the drilled holes on the surface of the entry board, which could hinder chip removal, resulting in poor hole wall quality and drill breakage.

This paper has a remarkably high industrial practicality in the PCB manufacture process.

Presents the study of the relationship between the deformation of the sewing thread and built‐in fibres as a consequence of a thread loading in the sewing process. The influence of the stitching speed and different twist numbers of PES thread on the alteration of the mechanical properties of the fibres twisted in the thread was studied for that purpose. On the basis of the received results it was found that with an increase in the number of the thread twist, the breaking tenacity and initial elasticity modulus of the fibres decrease, while the resulting deformation of the sewing thread between the sewing process was reflected as a decrease in the fineness and breaking extension of the fibres and as an increase in the value of the initial elasticity modulus of the fibres.

Solder masks are used universally on high density printed circuit boards to reduce the occurrence of solder bridges between adjacent tracks and pads. The use of solder mask can, however, have a deleterious effect on the solderability, i.e., the solder pull‐through and top‐land wetting, of plated‐through‐hole boards. This work considers, quantitatively, the specific effect on PTH board solderability of solder mask, considering in turn the three classes of photoimageable dry film, photoimageable ink and screen printed ink. Two modes of solderability degradation have been identified: a geometrical effect that depends on the thickness of the mask and its encroachment around the solderable pads, and a contamination effect arising from the development and washing of the photoimageable masks from surfaces to be soldered subsequently.