3D TSV hybrid pixel detector modules with ATLAS FE-I4 readout electronic chip

The through silicon via (TSV) technology has been introduced in a wide range of electronic packaging applications. Hybrid pixel detectors for X-ray imaging and for high-energy physics (HEP) can benefit from this technology as well. A 3D TSV prototype using the ATLAS FE-I4 readout electronic chip is described in this paper. This type of readout chip is already prepared for the TSV backside process providing a TSV landing pad in the first metal layer of the backend-of-line (BEOL) layer stack. Based on this precondition a TSV backside via-last process is developed on ATLAS FE-I4 readout chip wafer. The readout chip wafers were thinned to 100 µm and 80 µm final thickness and straight sidewall vias with 60 µm in diameter has been etched into the silicon from wafer backside using deep reactive ion etching (DRIE). The filling of the TSVs and the formation of the wafer backside interconnection were provided by a copper electroplating process. ATLAS FE-I4 readout chips with through silicon vias has been successfully tested, tuned and operated. In addition, hybrid pixel detector modules have been flip chip bonded using ATLAS FE-I4 TSV readout chips and planar sensor chips. After mounting the bare modules onto a support PCB, its full functionality has been verified with a source scan.

Effect of Rolling Orientation on the Microstructure and Mechanical Properties of AZ31B Mg Alloy

The magnesium AZ31B alloy has been utilized in a variety of applications within the automotive and aviation industries due to its high specific strength, low-cost processing, and low density. However, the AZ31B alloy generally has poor ductility and limited workability at room temperature. The objective of this study was to develop a manufacturing processing technique to increase the potential uses of this alloy. The methodology includes cold rolling and annealing using small pass reductions until the samples reached a final thickness of 1.78 mm (0.07 in). The samples were cut into 10.16 mm (0.4 in), 7.62 mm (0.3 in), and 5.08 mm (0.2 in) thicknesses prior to cold rolling and were rolled in 0-, 45-, and 90-degree rolling directions. The grain shapes and sizes were examined via optical microscopy. Tensile testing was conducted to determine the strength and ductility. Scanning electron microscopy (SEM) images were taken to evaluate fractured surfaces. All processes including rolling direction and furnace cooling or air cooling after annealing produced similar results of medium strength (245-250 MPa in ultimate strength, 122-127 MPa in yield) and greater than 22.5% elongations in very thin sheets. Samples rolled along the 45-degree direction produced the highest percent reduction in thickness.

Analysis of the Reasons for the Tearing of Strips of High-Strength Electrical Steels in Tandem Cold Rolling

High-strength non-oriented electro-technical steels with a low thickness possess excellent isotropy of electromagnetic and mechanical properties which is highly required in the production of high-efficiency electric motors. The manufacturing process of this type of steel includes very important and technologically complex routes such as hot rolling, cold rolling, temper rolling, or final heat treatment. The final thickness is responsible for the decrease in eddy-current losses and is effectively achieved during cold rolling by the tandem rolling mill. Industrial production of thin sheets of high-strength silicon steels in high-speed tandem rolling mills is a rather demanding technological operation due to the increased material brittleness that is mainly caused by the intensive solid solution and deformation strengthening processes, making the dislocation motion more complex. The main objective of this work was to investigate the distribution of local mechanical strains through the thickness of high silicon steel hot bands, generated during the cold rolling. The experimental samples were analysed by means of electron back-scattered diffraction and scanning electron microscopy. From the performed analyses, the correlation between the material workability and the nucleation of cracks causing the observed steel strip failure during the tandem cold rolling was characterized. Specifically, the microstructural, textural, misorientation, and fractographic analyses clearly show that the investigated hot band was characterized by a bimodal distribution of ferrite grains and the formation of intergranular cracks took place only between the grains with recrystallized and deformed structures.

Mechanical characterisation of the developing cell wall layers of tension wood fibres by Atomic Force Microscopy

Trees can generate large mechanical stresses at the stem periphery to control the orientation of their axes. This key factor in the biomechanical design of trees, named “maturation stress”, occurs in wood fibres during cellular maturation when their secondary cell wall thickens. In this study, the spatial and temporal stiffening kinetics of the different cell wall layers were recorded during fibre maturation on a sample of poplar tension wood using atomic force microscopy. The thickening of the different layers was also recorded. The stiffening of the CML, S1 and S2-layers was initially synchronous with the thickening of the S2 layer and continued a little after the S2-layer reached its final thickness as the G-layer begins to develop. In contrast, the global stiffness of the G-layer, which initially increased with its thickening, was almost stable long before it reached its final maximum thickness. A limited radial gradient of stiffness was observed in the G-layer, but it decreased sharply on the lumen side, where the new sub-layers are deposited during cell wall thickening. Although very similar at the ultrastructural and biochemical levels, the stiffening kinetics of the poplar G-layer appears to be very different from that described in maturing bast fibres.HighlightNew insights into the changes in mechanical properties within the cell wall of poplar tension wood fibres during maturation have been obtained using atomic force microscopy.

Strain State in Metal Sheet Axisymmetric Stretching with Variable Initial Thickness: Numerical and Experimental Results

This work presents a finite element model to analyze the distribution of the strains due to an axisymmetric stretching of a metal sheet. The sheet is characterized by a variable initial thickness. The resulting strain state is compared with that of a sheet with a constant initial thickness. The results of the present study allow asserting that the distribution of strains in the sheet can be controlled by setting opportunely the trend of the sheet initial thickness. In this way, it is possible to see that, starting from a sheet with variable initial thickness, a lighter final product is obtained, whose final thickness distribution is more uniform than that of the product obtained from a classic stretching process that requires a sheet with constant initial thickness. Encouraging results from an experimental activity carried out on an AA6060 aluminum alloy sheet, whose trend of initial thicknesses was prepared by removing material from a commercial sheet with a constant thickness, allow us to note the good agreement with what was theoretically highlighted.

Surface properties of a new lithium disilicate glass-ceramic after grinding

This study aimed to evaluate the effect of grinding on some surface properties of two lithium disilicate-based glass-ceramics, one experimental new product denominated LaMaV Press (UFSCar-Brazil) and another commercial known as IPS e-max Press (Ivoclar), in the context of simulated clinical adjustment. Discs (N = 24, 12 mm in diameter) were separated into four groups: LaMaV Press with no grinding (E), LaMaV Press after grinding (EG), IPS e-max Press with no grinding (C), and IPS e-max Press after grinding (CG). A 0.1-mm deep grinding was carried out on EG and CG samples (final thickness of 1.4 mm) using a diamond stone in a low-speed device. The E and C samples had the same thickness. The effect of grinding on the sample surfaces was evaluated by X-ray diffraction, mechanical and optical profilometry, scanning electron microscopy, goniometry, and Vickers hardness. The mean roughness (Ra) was evaluated by Kruskal–Wallis and Student–Newman–Keuls statistics. The surface energy (SE) by the sessile drop method and Vickers hardness (VH) were analyzed using two-way ANOVA. The Ra medians were E = 1.69 µm, EG = 1.57 µm, C = 1.45 µm, and CG = 1.13 µm with p = 0.0284. The SE and VH were similar for all materials and treatments. Grinding smoothed the surfaces and did not significantly alter the hardness and surface energy of both LaMaV Press and IPS e-max Press. These glass-ceramics presented similar surface properties, and clinical adjustments can be implemented without loss of performance of both materials.

Wearable Intracranial Pressure Monitoring Sensor for Infants

Monitoring of intracranial pressure (ICP) is important for patients at risk of raised ICP, which may indicate developing diseases in brains that can lead to brain damage or even death. Monitoring ICP can be invaluable in the management of patients suffering from brain injury or hydrocephalus. To date, invasive measurements are still the standard method for monitoring ICP; however, these methods can not only cause bleeding or infection but are also very inconvenient to use, particularly for infants. Currently, none of the non-invasive methods can provide sufficient accuracy and ease of use while allowing continuous monitoring in routine clinical use at low cost. Here, we have developed a wearable, non-invasive ICP sensor that can be used like a band-aid. For the fabrication of the ICP sensor, a novel freeze casting method was developed to encapsulate the liquid metal microstructures within thin and flexible polymers. The final thickness of the ICP sensor demonstrated is 500 µm and can be further reduced. Three different designs of ICP sensors were tested under various pressure actuation conditions as well as different temperature environments, where the measured pressure changes were stable with the largest stability coefficient of variation being only CV = 0.0206. In addition, the sensor output values showed an extremely high linear correlation (R2 > 0.9990) with the applied pressures.

Bonding of similar AA3105 aluminum alloy by Accumulative Roll Bonding process

Accumulative roll-bonding (ARB) is a novel plastic straining process aimed at bonding of similar and dissimilar metal combinations. Moreover, it is used recently to produce ultrafine grain materials and metal matrix reinforced composites to enhance mechanical, electrical, and corrosion resistance properties. This work presents an experimental study of roll bonding and accumulative roll bonding of similar AA3105 aluminum alloy at 300°C with a final thickness of 1.2 mm, focusing especially on bond strength evaluation and layers continuities. Tensile tests and three-points bending were performed to mechanical characterize the produced sheets in the various steps and based on the number of the cycles. The maximum strength was reached after 3 ARB cycles. After 4 cycles, the bonding interfaces have a uniform distribution through the sheet thickness, it is possible to distinguish only the interface formed in the last pass in the fracture surface, and no significant enhancement in strength was observed. Starting from 2 ARB cycles, micro-cracks were observed at the outer surface for bending angles greater than 90 deg, and at 180 deg all ARBed samples except A1 were failed.

Technique proposition and material comparison for surgery rope making

ABSTRACT: The most tension resistant, nonmetallic, surgical suture is 5 polyester. Comparing it’s resistance to those of the dogs’ cranial cruciate ligament and the canine gastrocnemius tendon’s up until they rupture, it’s possible to detect a considerably inferior resistance on the implant’s part. With the goal of achieving high mechanical resistances from sutures, these were grouped and twisted, resulting in a surgical rope that is adjustable to the patients needs. We analyzed manufacturing methodology, final conformation and tension resistance, based on three sutures models: “A” (1 polyglactin 910), “B” (1 polyester) and “C” (5 polyester). Considering averages of thickness and final load, the “B” implants obtained lower values than “A”, indicating that polyglactin 910 ropes are more resistant than those of polyester. Moreover, the “C” implants resulted in the highest values of load and thickness, indicating that final thickness is predictive towards tension resistance. Size 1 Polyester was the only one to generate linear regression for supported load, ensuring the 25,34 Newtons (N) increment to every suture added to the implant, which suggests its use for the creation of non absorbable ropes. The use of 1 polyglatctin 910 promotes load averages superior to 1 polyester;therefore, it is indicated for making absorbable surgical ropes.

Treatment of Turbine Blades via Cr2O3-Ni5%Al System Using Plasma Thermal Spraying

A plasma thermal spraying method was used for the purpose of coating the pre-prepared surfaces of turbine blades. Chromium oxide (Cr2O3) was used as a matrix reinforced with a metal material of Ni-5%Al at rates of 10, 20, 30, 40 and 50. The cermet powders were stirred for one hour then used to coat bases of steel (316L). A spray distance of 8cm was applied, and the binding material of Ni-22%Cr-10%Al-1%Y was sprayed with a thickness of 100μm. Then, the reinforced matrix was sprayed with a thickness of 300–350μm and the final thickness of the samples prepared was 400–450μm. The samples produced were sintered at 900°C for an hour and a half and underwent a hardness test, which gave the best hardness of the samples after sintering at a reinforcement rate of 50% by 612Hv. The lowest porosity value for the above rate was obtained at 3.88%. The results of the adhesive strength gave a value of 31.5 MPa after sintering and at the same 50% reinforcement. The results of the scanning electron microscope (SEM) showed that there was weakness and cracking in the coating layers at the low reinforcement ratios. However, the mechanical and physical properties improved with the increase in reinforcement ratios to reach the highest value of 50%. KEYWORDS Adhesion force, ceramites, scanning electron microscope, Vickers hardness