No description available.

No description available.

The lubrication of dry viscose fibres by a two component finish, and the lubrication of wet Iyocell fabric against metal, with various aqueous lubricant systems, has been studied. Secondary ion mass spectrometry (SIMS) was investigated as a means of providing direct chemical information from finished fibre surfaces. The composition and distribution of a two component finish applied to viscose fibres was determined successfully. When applying finish from a bath, the surface composition of the finished fibres was not controlled by the bath conditions. Increasing the concentration of finish in the bath did, however, increase the total amount of finish deposited, and increasing the concentration of antistat relative to lubricant in the bath increased the amount of antistat relative to lubricant deposited on the finished fibres. Fibre friction was determined using the capstan method. The friction forces, measured for finished viscose fibres, were correlated with the finish application conditions. Increasing the emulsion concentration in the finish bath reduced fibre/metal friction, but finish component ratio, emulsion concentration, dip time and bath temperature did not affect fibre/fibre friction. Spray applying the finish resulted in unfinished regions on the fibre surfaces and the electrical resistance of fibre bundles was not reduced. Bath application of finish did lower electrical resistance in comparison with unfinished fibre, but none of the bath deposition variables had a significant effect on electrical resistance.

No description available.

Infertility affects ~20% of couples in Europe and in 50% of cases the problem lies with the male. The development of assisted reproductive technologies (ART) such as in vitro fertilisation (IVF) and intra-cytoplasmic spermatozoa injection (ICSI) has allowed some couples to overcome male-factor infertility. However concerns remain over the increasing use of ART as elevated levels of DNA damage in sperm from infertile men have been reported and a link between DNA damage in sperm and early embryonic failure has been demonstrated. DNA damage in sperm, caused by oxidative stress may also be passed on from father to child resulting in an increased incidence of childhood cancer. This has led to fears that the use of damaged sperm in ART could contribute to early embryonic failure and/or birth defects. The studies described in this thesis used mouse models to investigate the relationship between DNA integrity in male germ cells and male fertility. This was achieved by studying both the effects of targeted ablation of genes involved in DNA repair and the impact of scrotal heat stress on testicular function and sperm DNA integrity. Three lines of transgenic mice with deletions in genes involved in genomic integrity (Ercc1, Msh2 and p53) were studied. All three genes are expressed in the testis. These studies confirmed and extended studies on Ercc1 knockout (-/-) mice showing reduced germ cell complement, increased apopotosis, an increased percentage of damaged sperm and demonstrated for the first time that depletion of Ercc1 results in an increased incidence of unrepaired double strand DNA breaks (DSB) in pachytene spermatocytes. The persistence of DSBs in spermatocytes and abnormal sperm chromatin structure confirmed that the repair functions of Ercc1 are essential for normal germ cell maturation. In the p53-/- mice these studies showed for the first time that there was an increase in DSBs in spermatocytes and an increase in numbers of sperm with damaged DNA. The level of apoptosis was also increased in the testes suggesting that caspase-3 mediated apoptosis is not entirely p53 dependent as been previously suggested. These studies demonstrated for the first time that targeted ablation of Msh2 compromises germ cell complement and as in the Ercc1-/- this resulted in gaps in the seminiferous epithelium consistent with clonal loss of germ cells. Consistent with a role for MSH2 in mismatch repair no DSBs were detected in spermatocytes from Msh2-/-. Testicular function is temperature dependant and due to their location in the scrotum testes are normally kept between 2ºC and 8ºC below core body temperature. In mice transient scrotal heat stress (30 minutes at 38°C, 40°C and 42°C) disrupted testicular function. Analysis of sperm and testis parameters revealed that stress at 38°C was sufficient to have subtle effects on epididymal function but the higher temperatures had additional consequences for testicular function which resulted in DNA damage in spermatocytes, germ cells loss and increased apoptosis. Further studies into the pathways of apoptosis demonstrated that the mitochondrial/intrinsic pathway plays a role in heat stress response. The fertility of males was altered in those heated to 42°C resulting in reduced pregnancy rate and litter size. Given that the paternal genome is reported to be required for the development of extraembryonic tissues and this will influence growth of the embryo, it was interesting to note an increase in resorption sites in pregnancies using 40°C males. IVF was used to demonstrate that embryos formed using sperm from males stressed at 42°C were compromised between the 4-cell and blastocyst stage suggesting that though sperm with DNA damage are still capable of fertilisation, the paternal DNA was introducing genomic instability to the embryo and having fatal effects on development. These studies have also shown that one possible underlying cause of the disturbance in testicular function is hypoxia, as a marked increase in Hif1 alpha (a marker of hypoxia) mRNA and relocalisation of the protein was observed in the testis. In conclusion, DNA damage in the male germ line caused either by induced stress, or by targeted ablation of DNA repair genes, can disrupt testicular architecture, function and therefore the fertility of mice. These data have demonstrated that deletion of Ercc1, Msh2 and p53 can have differential but overlapping affects on germ cell function and sperm production and that increased scrotal temperature can cause subfertility in male mice. This study has provided further confirmation of possible male-mediated effects on embryo survival and these findings should be taken into consideration when using sperm from infertile men in IVF/ICSI treatments where the normal quality control processes involved in fertilisation are bypassed.

Intermittent Pneumatic Compression (IPC) use as a tool for recovery after exercise has recently become widespread among athletes. While there is strong anecdotal support for IPC, little research has been done to show its effectiveness in recovery. Eight collegiate football athletes were recruited and subjected to IPC or control conditions in a randomized crossover manner during off-season training. Countermovement jump (CMJ) and 10m sprint were evaluated before training, at 3 and 24 hours following training. Self-reported soreness, blood markers of inflammation [interleukin-6, interleukin-10, and monocyte chemoattractant protein-1 (MCP-1)] and muscle damage (myoglobin) were measured before training, post-training, post-recovery and at 3 and 24 hours post-training. Significant time effects were observed in MCP-1 and myoglobin (p < 0.05) indicating an inflammatory response and muscle damage. No group differences (p > 0.05) were observed between recovery interventions for all measures, suggesting that the IPC protocol used was not effective in this population. / February 2017

The non-native Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) has been grown to a limited extent in the southern part of Sweden since the early 1900s. A more extensive use has probably been curtailed by its known susceptibility to damage by frost, pine weevil and other pests. Limited access to vital seedlings of suitable provenances has also restricted its more widespread growth. The need for valuable species that will grow well through ongoing climate change has increased the interest for Douglas fir in Sweden. This thesis addresses a number of important questions relating to the planting of Douglas fir in Sweden: seedling storability, freezing tolerance, timing of bud burst, frost damage and seedling response to site preparation. Seven Douglas fir provenances originating from British Columbia, Canada were used in the experiments and where applicable, compared with a local provenance of Norway spruce (Picea abies (L.) Karst.). The early bud burst of interior Douglas fir provenances, observed both in greenhouse tests and in the field, results in a high risk of damage by late spring frost. This type of damage does not seem, however, to be fatal and does not obviously retard the early growth of seedlings. The difference in growth between coastal and interior provenances was insignificant, but survival was greater for interior than for coastal provenances. All the provenances of Douglas fir studied showed a later development of freezing tolerance of shoots and roots in the autumn than Norway spruce, with the coastal provenances developing such tolerance even later than interior provenances. This could be a contributory cause for the severe damage by winter desiccation observed on seedlings of coastal origin. A thorough site preparation proved to be an effective way to increase survival and root growth. Interior provenances of Douglas fir became ready for storage earlier in autumn than coastal provenances. When freezing tolerance of shoots had increased sufficiently, Douglas fir seedlings could safely be kept in frozen storage using the same procedures used for Norway spruce. The results emphasise the need to gain further knowledge about how the remaining obstacles to establishment of Douglas fir could be reduced with different silviculture methods.

Crack propagation and branching are modeled using nonlocal peridynamic theory. One major advantage of this nonlocal theory based analysis tool is the unifying approach towards material behavior modeling- irrespective of whether the crack is formed in the material or not. No separate damage law is needed for crack initiation and propagation. This theory overcomes the weaknesses of existing continuum mechanics based numerical tools (e.g. FEM, XFEM etc.) for identifying fracture modes and does not require any simplifying assumptions. Cracks grow autonomously and not necessarily along a prescribed path. However, in some special situations such as in case of ductile fracture, the damage evolution and failure depend on parameters characterizing the local stress state instead of peridynamic damage modeling technique developed for brittle fracture. For brittle fracture modeling the bond is simply broken when the failure criterion is satisfied. This simulation helps us to design more reliable modeling tool for crack propagation and branching in both brittle and ductile materials. Peridynamic analysis has been found to be very demanding computationally, particularly for real-world structures (e.g. vehicles, aircrafts, etc.). It also requires a very expensive visualization process. The goal of this paper is to bring awareness to researchers the impact of this cutting-edge simulation tool for a better understanding of the cracked material response. A computer code has been developed to implement the peridynamic theory based modeling tool for two-dimensional analysis. A good agreement between our predictions and previously published results is observed. Some interesting new results that have not been reported earlier by others are also obtained and presented in this paper. The final objective of this investigation is to increase the mechanics knowledge of self-similar and self-affine cracks.

Approved for public release; distribution is unlimited / A five microsecond, 15 joule, pulsed C0₂ Laser was used to irradiate polished 2024 aluminum targets. The target voltage response (TVR) was measured with respect to the incident laser radiation and showed a pulse width on the order of 30 nanoseconds. The voltage was measured at values from 22 to 140 volts with resistances varying from one ohm to two mega-ohms. The TVR was correlated to the emission and blow-off of electrons from the target surface and the possible ignition of a Laser Supported Detonation wave. The TVR, laser pulse, and flash associated with target surface breakdown were time correlated and shown to happen within the first 170 nanoseconds of the five microsecond laser pulse. Currents up to 500 amps were observed when the resistance to ground was reduced to less than 1 ohm. Also, the magnitude of the TVR was shown to be a function of background gas pressure. / http://archive.org/details/targetvoltageres00hark / Lieutenant, United States Navy

Following the studies of natural frequency based damage detection methods, an advanced technique for damage detection and localization in beam-type structures using a vibration characteristic tuning procedure is developed by an optimal design of piezoelectric materials. Piezoelectric sensors and actuators are mounted on the surface of the host beam to generate excitations for the tuning via a feedback process. The excitations induced by the piezoelectric effect are used to magnify the effect of the damage on the change of the natural frequencies of the damaged structure to realize the high detection sensitivity. Based on the vibration characteristic tuning procedure, a scan-tuning methodology for damage detection and localization is proposed. From analytical simulations, both crack and delamination damage in the beams are detected and located with over 20% change in the natural frequencies. Finite element method (FEM) simulations are conducted to verify the effectiveness of the proposed methodology. / October 2016