The preparation of Carbon Fibre Reinforced Polymers (CFRP) surfaces for adhesive bonding has been widely reported. Such reports include laser texturing using both near-infrared (IR) lasers and ultraviolet (UV) lasers. In this report, we present, for the first time, findings showing that surface treatment of CFRP using incoherent UV light, at 254 nm wavelength, can increase the adhesive bonding strength of CFRP by 75 % compared to nontreated samples. It is also around 10 % stronger than NIR laser-textured samples. However, combination treatments, where the UV irradiation is conducted either before or after laser texturing did not give a significant benefit over the laser-textured samples. A germicidal 46 W 254 nm UV lamp was used for the UV light treatment, while an IR nanosecond pulsed fibre laser operating at 1064 nm was used for the laser texturing treatment. The material tested was an autoclave-cured T700 CFRP composite. The wettability of the treated CFRP surfaces and the adhesive bonding were quantitatively assessed. This study concludes that low-cost incoherent UV treatment effectively reduces the water contact angle of the CFRP surface and activates CFRP surfaces. All treatments led to bonding strengths at least 50% greater than for the untreated surfaces. The predominant failure mode for UV-treated samples was Cohesive Substrate Failure (CSF), indicating that the adhesion strength exceeded the interlaminar shear strength of the CFRP material. All samples treated with the laser (including combined treatment with UV) exhibited Light Fibre Tear Failure.

Shaping or splitting of a Gaussian beam is often desired to optimise laser–material interactions, improving throughput and quality. This can be achieved holographically using liquid crystal-on-silicon spatial light modulators (LC-SLMs). Until recently, maximum exposure has been limited to circa 120 W average power with a Gaussian profile, restricting potential applications due to the non-linear (NL) phase response of the liquid crystal above this threshold. In this study, we present experimental tests of a new SLM device, demonstrating high first-order diffraction efficiency of η = 0.98 ± 0.01 at 300 W average power and a phase range Δφ > 2π at P = 383 W, an exceptional performance. The numerically calculated device temperature response with power closely matches that measured, supporting the higher power-handling capability. Surface modification of mild steel and molybdenum up to P = 350 W exposure is demonstrated when employing a single-mode (SM) fibre laser source. Exposure on mild steel with a vortex beam (m = +6) displays numerous ringed regions with varying micro-structures and clear elemental separation created by the radial heat flow. On molybdenum, with multi-spot Gaussian exposure, both MoO3 films and recrystallisation rings were observed, exposure-dependent. The step change in device capability will accelerate new applications for this LC-SLM in both subtractive and additive manufacturing.

The use of a pulsed laser system to manufacture parallel streamwise riblets on the plates of a heat exchanger is reported. There are certain laser system elements that can influence the quality of a micrometre texture geometry; among these, there was a focus on laser incubation effect on obtaining greater depth of the riblets. Surface roughness was always considered to keep the heat transfer efficiency high. The heat exchanging process was measured in two flow regimes: laminar and turbulent. In laminar flow, the surface texture slightly deteriorated the heat transfer rate. However, small improvement in the heat transfer rate was observed in turbulent flow.

The cast iron is widely used in mechanical parts due to its good properties, as damping, good fluidity, resistance to deformation, excellent machinability and low cost. However, the number of its applications are reduced because its low corrosion, wear and friction resistance. The microstructure of the metallic materials has high influence on these properties. Laser hardening can improve these properties via designing of the microstructure. The evaluation of the laser parameter influence on the microstructural features is vital for a correct design of the microstructure and therefore, good improvement of the metallic material properties. Although the various laser parameter influence has been analysed on sundry papers, the influence of the distance from focal point and scan speed in the laser hardening microstructures has been rarely evaluated in the literature. Thus, the influence of this parameter on the microstructures generated through laser hardening is the subject matter of this work. The experiments were carried out with continuous wave carbon dioxide laser on samples of ground cast iron. The atmosphere was air flow at 0.7MPa, the laser operated at 100W and the scan rates were 1mm/s and 5mm/s. The distances to focal point of the laser beams ranged from 0.0mm to 5.6mm. The microstructures of the samples were revealed via nital and evaluated with optical microscopy. This work shown that the microstructure of gray iron cast can be designed by mean of laser hardening. In addition, laser hardened zones had various microstructures (e.g. austenitic, martensitic, pearlite and dendritic). The type of the microstructures in laser treated zones was determined by distance from focal point and scan speed. Moreover, the width and the depth of the laser hardened zones were generally enlarged with the increasing of the distance from focal point. Furthermore, the laser irradiation at slow rates, i.e. 1mm/s, produced laser hardened zones larger than laser scan at 5mm/s. In future works, the hardness, wear and friction resistance of the laser hardened samples will be evaluated because the literature review indicates that austenitic and martensitic microstructures show high values of these properties.

Different microstructures were created on the surface of a polycrystalline diamond plate (obtained by microwave plasma-enhanced chemical vapor deposition—MW PECVD process) by use of a nanosecond pulsed DPSS (diode pumped solid state) laser with a 355 nm wavelength and a galvanometer scanning system. Different average powers (5 to 11 W), scanning speeds (50 to 400 mm/s) and scan line spacings (“hatch spacing”) (5 to 20 µm) were applied. The microstructures were then examined using scanning electron microscopy, confocal microscopy and Raman spectroscopy techniques. Microstructures exhibiting excellent geometry were obtained. The precise geometries of the microstructures, exhibiting good perpendicularity, deep channels and smooth surfaces show that the laser microprocessing can be applied in manufacturing diamond microfluidic devices. Raman spectra show small differences depending on the process parameters used. In some cases, the diamond band (at 1332 cm−1) after laser modification of material is only slightly wider and shifted, but with no additional peaks, indicating that the diamond is almost not changed after laser interaction. Some parameters did show that the modification of material had occurred and additional peaks in Raman spectra (typical for low-quality chemical vapor deposition CVD diamond) appeared, indicating the growing disorder of material or manufacturing of the new carbon phase.

Laser dimple generation can functionalise ceramic surfaces. Dimple characteristics determine the functionalised surface properties, which has numerous applications. Laser parameters and material properties are key factors in the design of the dimple features. Pulse energy, Ep, and average surface roughness, Ra, are important parameters in the dimple production. Thus, the influence of the Ep of InfraRed (IR) nanosecond pulsed laser on the dimple characteristics generated on two Cr2O3 surfaces (as-received and polished) are studied in this work. The increase of the Ep increased the dimples features (Diameter, D, and depth, L). Polished surfaces gave dimples with increased depth while dimples produced on as-received samples were shallow. The energy fluence ablation threshold, φth, is higher for as-received surface than for polished Cr2O3.

Inconel is used largely in aerospace industry for the manufacturing of jet engine components, where high heat resistance materials are preferred. Inconel has special properties such as high strength to weight ratio, low thermal conductivity and poor machinability. This has led to numerous researches into the machinability of this material that still poses challenges to unexperienced new manufacturers. The work presented here, employs low frequency oscillation to induce vibratory grinding of Inconel 718 with reduced coolant application at very low pressure. A porous aluminium oxide-grinding wheel was used for the experimental work with and without oscillations. The experimental results showed that the superimposition of vibration improved the overall process performance. A reduction of over 30% in grinding cutting forces was recorded, along with an extended wheel life, increase in material removal rate and improved surface roughness quality.

Whilst not explaining all social behaviour and organisation, dominance is nevertheless an important dimension of human social interaction.It has been hypothesized that gaze behaviour reflects the dominance hierarchy of primate groups and several studies have demonstrated that cues associated with social status also influence human gaze.These studies overwhelmingly involve male participants and sex differences in coalition formation, status seeking, risk taking and dominance-related behaviour have all been explained by the fact that males needed to compete for mates while females supposedly did not.Indeed, until comparatively recently it was thought that dominance contests were of little consequence for females.However, there is increasing evidence to suggest that competitiveness is useful for females and there are attendant benefits conferred upon those with high status.Thus, it is important to understand these status-gaze relationships in women.Sixty heterosexual, caucasian female participants (mean age=22.1,SD=3.16) competed in a dyadic non-physical status encounter (woodblock game Jenga).Dyads were unknown to each other and matched by menstrual phase (follicular/luteal) or contraceptive use.Winners were congratulated and received £5 to accentuate status disparity.In the two minutes following competition participants sat apart but in sight of each other.The investigator left the room and gaze behaviour was recorded by video camera.The length of time each participant spent looking at their opponent was related to competition outcome: winners (M=3.96,SD=1.72), losers (M=7.34,SD=4.32).There were main effects for outcome, F(1,54)=22.47, p<0.0001 and menstrual phase/contraceptive use F(2,54)=5.34,p=0.008.Follicular and Luteal phase did not differ from each other significantly.The interaction between outcome and menstrual phase/ contraceptive use was significant, F(2,54)=8.75,p<0.001, with contraceptive use reversing the findings of longer gaze time in the loss condition in normally cycling women.Our results support the hypothesis that female gaze behaviour is responsive to the outcome of status encounters.

This paper presents the results of carbon nanoparticles (CNPs) production by infrared laser ablation of a graphite or a polycrystalline diamond target, submerged in one of two solvents, water or isopropanol. The targets were irradiated using a SPI fibre laser with a wavelength of 1064nm being operated at different average powers. After laser-assisted synthesis of CNPs, the resulting colloids, i.e particles in a liquid medium, were examined using the analytical techniques of dynamic light scattering, UV-Vis, Raman spectroscopy and fluorescence spectroscopy. The results show that the properties of CNPs strongly depend on processing conditions of the liquid phase-pulsed laser ablation (LP-PLA) process. In particular, the size of nanoparticles produced are affected by the processing parameters of the laser ablation. The results show that the laser processing of a graphite target in deionised water and in isopropanol produces carbon nanoparticles with properties that are beneficial for various biochemical and biomedical applications.

Studies have shown that surfaces having micro and nano-scale features can be used to control cell behaviours including; cell proliferation, migration and adhesion. The aim of this work was to compare the use of laser processing and abrasive polishing to develop micro/nano-patterned polyurethane substrates for controlling fibroblast cell adhesion, migration and proliferation. Laser processing in a directional manner resulted in polyurethane surfaces having a ploughed field effect with micron-scale features. In contrast, abrasive polishing in a directional and random manner resulted in polyurethane surfaces having sub-micron scale features orientated in a linear or random manner. Results show that when compared with flat (non-patterned) polymer, both the laser processed and abrasive polished surface having randomly organised features, promoted significantly greater cell adhesion, while also enhancing cell proliferation after 72 h. In contrast, the abrasive polished surface having linear features did not enhance cell adhesion or proliferation when compared to the flat surface. For cell migration, the cells growing on the laser processed and abrasively polished random surface showed decreased levels of migration when compared to the flat surface. This study shows that both abrasive polishing and laser processing can be used to produce surfaces having features on the nano-scale and micron-scale, respectively. Surfaces produced using both techniques can be used to promote fibroblast cell adhesion and proliferation. Thus both methods offer a viable alternative to using lithographic techniques for developing patterned surfaces. In particular, abrasive polishing is an attractive method due to it being a simple, rapid and inexpensive method that can be used to produce surfaces having features on a comparable scale to more expensive, multi-step methods.

High heat conductivity and high heat capacity make ceramic substrates indispensable to the manufacture of Multi-Chip Modules (MCM) and power electronics. In this paper a detailed description of the integration process of optical lines on to ceramic substrates is presented. The manufacturing of microgrooves in ceramic substrates and the process of integration of optical fibres and active elements is described. Coupling active elements to optical fibre is also presented. Through such an integrated optical line a 4Gbps signal was transmitted.

Laser surface alloying is a powerful technique for improving the mechanical and chemical properties of engineering components. In this study, laser surface irradiation process employed in the surface modification off 316L stainless steel substrate using hydroxyapatite-titanium oxide to provide a composite ceramic layer for the suitability of applying this technology to improve the biocompatibility of medical alloys and implants. Fusion of the metal surface incorporating hydroxyapatite-titania ceramic particles using a 30 W Nd:YAG laser at different laser powers, 40, 50 and 70% power and a scan speed of 40 mm s(-1) was observed to adopt the optimum condition of ceramic deposition. Coatings were evaluated in terms of microstructure, surface morphology, composition biocompatibility using XRD, ATR-FTIR, SEM and EDS. Evaluation of the in vitro bioactivity by soaking the treated metal in SBF for 10 days showed the deposition of biomimetic apatite.

There is increasing interest in the use of lasers to modify the wettability of surfaces. Here we report on the use of a 20W nS pulsed IR fibre laser to create strong hydrophobicity on the surface of aluminium sheets. This is unexpected, hydrophobicity is usually associated solely with femto- or pico- second laser processing. At a 20W average power level the area coverage rate is too small for many industrial applications. Further trials using a 800W DPSS laser are described and the ability of this system to change surface wettability at a much higher production rate are indicated. There is little reported literature on surface texturing at higher average power levels. Indications of the productivity, or surface coverage rate, are given.

A ‘0/π’ phase pupil mask was developed to extend the depth of field of a circularly symmetric optical microscope imaging system. The modulation transfer function curves, the normalized point spread function figures and the spot diagrams of the imaging system with the optimal mask were analyzed and simulated. The results show that the large depth of field imaging system with the ‘0/π’ phase pupil mask has a high resolution in a long frequency band and can obtain clear images without any post-processing. The experimental results also demonstrate that the depth of field of the imaging system is extended successfully.

As the demand grows for complex thin electronic components, laser micromachining will continue to provide unique opportunities. A thin PCB film processing technology based on laser direct ablation was developed to manufacture high-performance, large-area and flexible electronic boards. Structure widths of 25 mu m are possible with outstanding positioning accuracy and without damaging the substrate. The present study illustrates this novel process that uses a computer controlled laser systems to create complex micromachined open ring resonators for the manufacture of electromagnetic metamaterials.Employing two analytical techniques, optical microscopy and Scanning Electron Microscopy, it has been demonstrated that rapid laser patterning of rigid and flexible PCB can be undertaken, and that it completely removes all the copper without noticeable substrate damage. (C) 2014 Elsevier Ltd. All rights reserved.

Previous research has implicated the involvement of androgens in sex-role orientation in males, from studies of 2nd to 4th digit ratio (a purported marker of prenatal testosterone). The present pilot study investigates the relationship between salivary testosterone levels and sex-role orientation using Bem Sex Role Inventory (BSRI) scores in adult males. Twenty-one males (aged 18-24) completed the BSRI and provided saliva samples for assay. BSRI Femininity scores were significantly negatively correlated with testosterone levels; the higher the Femininity scores, the lower the testosterone levels. There was no relation of BSRI Masculinity scores with testosterone levels. Our preliminary results add to the research suggesting that sex-role orientation in males may be partially related to underlying hormone levels.

A novel neutron spin-echo spectrometer with superconducting main coils enabling enclosure by a double walled μ-metal magnetic shielding chamber has been built and set into operation at the spallation neutron source in Oak Ridge. The layout of the spectrometer is described. Performance with emphasis on the superconducting main solenoids and the time-of-flight operation is described. Data on resolution, stability and first experiments are shown.

The use of high power laser technology in the cleaning and dressing of grinding wheels has been the subject of several research projects worldwide and over the last 30 years. Several projects have reported beneficial outcomes however the process has not been implemented in production. The arrival of fibre lasers may provide a viable laser source for cleaning, and ultimately dressing, of wheels. This paper reports on some preliminary data confirming this potential and that supports the need for further research effort.

The interest in laser material processing of Carbon Fibre Reinforced Plastic (CFRP) over the past few years has increased, especially in the aerospace industry. A number of different laser groups around the world are investigating different laser sources for the express reason of developing a laser material processing centre for machining CFRP for the aerospace and automotive industry. This paper reports on the work of two such groups, in the UK and Germany, who are using fibre laser technology and a diode pumped solid state laser system. The initial results from the two studies are reported and show that these two very different laser systems offer processing capability with respect to machining CFRP.