Determination of Fracture Toughness of Anisotropic Rocks Under Water Vapour Pressure by Semi-Circular Bend Test

Failure of rock materials is a process of crack propagation. Crack initiation takes place when the crack tip stress intensity K reaches a critical value called fracture toughness, K1C. The rock fracture toughness is known to be affected by the surrounding environment such as temperature, confining pressure and humidity. In order to examine the effect of humidity a series of semi-circular bend tests were performed under various water vapour pressures in a rock material that is known to be anisotropic. Water vapour promotes stress corrosion of rock and therefore the fracture toughness was found to have a decreasing trend with increasing water vapour pressure. The rate of decreasing the fracture toughness depends on the microcrack density that promotes the migration of water vapour into the rock. Also in an anisotropic rock the fracture toughness depends on the direction of crack in relation to the anisotropy of the rock material

Versatile implementation in angle-resolved optical microscopy: its application to local spectrometry of microcavities with PIC-J-aggregates

Versatile novel implementations in microspectroscopy are developed, which can provide angle-resolved optical spectroscopy at local sample areas almost in diffraction limit. By selecting focus position of light flux incident within the back focal plane of the objective lens radially from the position of the optical axis of the microscope with employing off-centered pinhole, we can obtain parallel beam with oblique incidence and its angle tuning at the sample surface. In this paper, we describe our specific optical setup and its practical working principle in detail. We report, as a demonstration of its performance, our latest studies on optical properties of cavity polariton states in the so-called quantum microcavity structures, which contain molecular J-aggregates of pseudoisocyanine (PIC) dye as active working materials. By using the microscope technique, we obtain a fair amount of improvement in the linewidth observation of cavity polariton spectra

Contribution of Microfinance Credit on Poverty Reduction among the Agricultural Rural Women in Keiyo North District, Elgeyo-Marakwet County, Kenya

Microfinance institutions provide small loans to rural women to improve their living standards. The main purpose of microfinance credit programme is to break the vicious cycle of poverty among the rural women by providing them with capital. Poverty is a global problem; more than 1.3 billion people worldwide live below the poverty line, 70% of them being women. In Keiyo North district, 48% of the population lives below the poverty line with women constituting 65% of those living below the poverty line. However, less rural women in Keiyo North district participate in the microfinance credit programme despite the fact that Kenya Women Finance Trust (KWFT) operates in all the 13 sub-locations in the district. This study sought to investigate the contribution of microfinance credit on poverty reduction among the rural women in Keiyo North district. The study used a descriptive survey design to collect data. The target population was 220 of the rural women participating in groups in microfinance credit programme from which a sample of 130 rural women was drawn. An open and close-ended questionnaire was used. A pilot study was conducted among the 30 KWFT rural women participants and a Cronbach’s Apha coefficient reliability of 0.71 was attained. The validity of the instrument was ascertained by experts from Agricultural Education and Extension in the Faculty of Education and Community studies and supervisors of Egerton University. Data was analyzed using chi-square α=0.05 significance level. Results indicated that microfinance credit programme has improved household level of income and acquisition of assets among the rural women in Keiyo North district. In addition, the rural women can also afford health care services for their families as a result of participating in microfinance credit programme. The study recommends that microfinance institutions (MFIs) should encourage more rural women to participate in microfinance credit programme to increase their levels of income and raise their household assets ownership. The county government should sensitize more rural women on the need to join the microfinance credit programme in order to boost their ability to afford health care services for their families. Keywords: Microfinance credit, poverty, Income, Asset acquisition, Health care, Agricultural rural women

Fabrication, characterization and its local reflection properties of a metal-mirror microcavity with high concentrated PIC J-aggregates

We have investigated reflection properties of light-matter strong coupling in a planar metal-mirror microcavity with highly concentrated PIC J-aggregates. Large vacuum Rabi-splitting ranging from 100 to 250 meV is obtained depending on the concentration of the J-aggregates. The factors for providing these large Rabi-splitting will be discussed based on its concentration dependence. We also present our recent study focused on microscopic reflection properties of the microcavity. We have improved microscope optics which enables us to measure local reflection spectra within 0.3-m-diameter area. Observation of incident-light-angle dependence becomes possible. We found existence of micrometer-scale inhomogeneity in the Rabi-splitting (e.g. ±10% in a region), which will be interpreted mainly by the spatial distribution of J’s in the active layer

The rys quadrature revisited: a novel formulation for the efficient computation of electron repulsion integrals over gaussian functions

A novel formulation of the Rys quadrature algorithm for the calculation of the electron repulsion integrals over Gaussian basis functions is presented. The new algorithm is specifically designed for high contractions. As for the original Rys quadrature algorithm, the new algorithm is very efficient for high angular momentum functions. In addition it is also equally efficient for low angular momentum functions. The new algorithm takes unique advantage of (1) the numerical Rys quadrature methodology in (2) dealing with charge distributions a la McMurchie-Davidson and in (3) scaling integral blocks as a means of transferring angular momentum a la Gill-Head-Gordon-Pople. An analysis of the algorithm suggests very favorable floating-point operation count

The impact of computed high b-value images on the diagnostic accuracy of DWI for prostate cancer: A receiver operating characteristics analysis.

To evaluate the performance of computed high b value diffusion-weighted images (DWI) in prostate cancer detection. 97 consecutive patients who had undergone multiparametric MRI of the prostate followed by biopsy were reviewed. Five radiologists independently scored 138 lesions on native high b-value images (b = 1200 s/mm2), apparent diffusion coefficient (ADC) maps, and computed high b-value images (contrast equivalent to b = 2000 s/mm2) to compare their diagnostic accuracy. Receiver operating characteristic (ROC) analysis and McNemar's test were performed to assess the relative performance of computed high b value DWI, native high b-value DWI and ADC maps. No significant difference existed in the area under the curve (AUC) for ROCs comparing B1200 (b = 1200 s/mm2) to computed B2000 (c-B2000) in 5 readers. In 4 of 5 readers c-B2000 had significantly increased sensitivity and/or decreased specificity compared to B1200 (McNemar's p < 0.05), at selected thresholds of interpretation. ADC maps were less accurate than B1200 or c-B2000 for 2 of 5 readers (P < 0.05). This study detected no consistent improvement in overall diagnostic accuracy using c-B2000, compared with B1200 images. Readers detected more cancer with c-B2000 images (increased sensitivity) but also more false positive findings (decreased specificity)