The design and investigation of the self-assembly of dimers with two nematic phases

A series of non-symmetric dimers were synthesised containing either cyanobiphenyl or difluoroterphenyl moieties on one side and a range of long, short, bent, polar or apolar mesogens on the other side of the molecules. The dielectric anisotropy of the mesogens was varied systematically. The systems were characterised by differential scanning calorimetry (DSC), optical polarizing microscopy (OPM) and detailed X-ray diffraction (XRD) studies, both in the nematic and the Nx phase. The results are compared and structure properties relationships are discussed. A model for the assembly in the Nx phase is developed discussing Ntb structures, coaxial helices, swiss roll structures and chiral domain formation

Enhanced oil recovery by CO2 injection in carbonate reservoirs.

The majority of carbonate reservoirs have low porosity and permeability in general because of having a high amount of matrixes that make a heterogeneous reservoir, however high permeable layers are fractured. This study shows the effect of carbon dioxide injection on the oil recovery factor using an ECLIPSE 300 compositional reservoir simulator for 3D modelling and the change of carbonate components reaction during CO2 injection in experimental work. In addition, a high recovery factor has been recorded during miscible CO2 injection compared to immiscible injection. Water alternative gas (WAG) has been used as an enhanced oil recovery (EOR) method to overcome an unfavourable mobility ratio of CO2 flooding. Miscible CO2 injection with the aid of WAG has also had a great impact on the dissolution of carbonate components in dissolving calcite and dolomite components. Consequently, CO2 flooding has a relatively low recovery factor without any EOR techniques such as gravity stable displacement, WAG or mobility control. CO2 injection below minimum miscibility pressure (MMP) reduces CO2 emission, while it takes too long time to maintain reservoir pressure. On the other hand, CO2 flooding above MMP improves pressure maintenance; causes oil swelling, and increases the oil density

The stabilisation of the Nx phase in mixtures

The phase behaviour of mixtures between two symmetric dimers, CBC9CB and the ether-linked analogue CBOC9OCB was investigated by Polarizing Optical Microscopy (POM), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) studies. The dimeric constituents are fully miscible and the construction of a temperature-composition phase diagram reveals a surprising amplification of the stability of the Nx phase in compositions of up to 37 wt% of CBOC9OCB in CBC9CB. The origin for this enhancement of stability is discussed and an explanation based on chiral recognition is developed

Deuteron and proton NMR study of D₂, p-dichlorobenzene and 1,3,5-trichlorobenzene in bimesogenic liquid crystals with two nematic phases

The solutes dideuterium, 1,3,5-trichlorobenzene and p-dichlorobenzene (pdcb) are co-dissolved in a 61/39 wt% mixture of CBC9CB/5CB, a bimesogenic liquid crystal with two nematic phases. NMR spectra are collected for each solute. The local electric field gradient (FZZ) is obtained from the dideuterium spectrum. A double Maier-Saupe potential (MSMS) is used to rationalize the order parameters of pdcb. The liquid-crystal fields G₁ and G₂ are taken to be due to size and shape interactions and interactions between the solute molecular quadrupole and the mean FZZ of the medium. The FZZ’s obtained from D₂ and G₂ (from pdcb) are compared and discussed

Level of Serum Uric Acid in Pre-eclamptic and Normal Pregnant Women

Objective: The objective of study was to find out serum uric acid level in normal andpreeclamptic pregnant women of third trimester visiting outpatient department of obstetrics and gynecology of Bahawal Victoria Hospital, Bahawalpur. Methodology: It was a cross sectional descriptive study conducted form July 2018 to June 2019. All primigravida women of age 18-35 years in third trimester of singleton pregnancy attending in Obstetrics and Gynecology Outpatient Department of Bahawal Victoria Hospital in study duration were included in the study. Statistical analysis was performed by using SPSS version 14. Chi-square test was performed to find the statistical difference regarding uric acid distribution between groups and ‘p' value <0.05 was considered as a lowest level of significance. Results: Out of total 1212 women 84.6% were normal and 15.4% had preeclampsia. In our study out of 187 preeclamptic women, 63.6% had raised serum uric acid level and out of 268 normal pregnant women uric acid level was raised in only 39.5%. Results were found statistically significant. Conclusion: Results of our study suggest that serum uric acid level in pregnant women can be used as a useful and inexpensive marker in prediction of preeclampsia and preventive measures can be taken accordingly

Saudi SCD patients’ symptoms and quality of life relative to the number of ED visits

Background Individuals living with sickle cell disease (SCD) have significantly increased emergency department (ED) use compared to the general population. In Saudi Arabia, health care is free for all individuals and therefore has no bearing on increased ED visits. However, little is known about the relationship between quality of life (QoL) and frequency of acute care utilization in this patient population. Methods A cross-sectional study was conducted on 366 patients with SCD who attended the outpatient department at King Fahad Hospital, Hofuf, Saudi Arabia. Data were collected through self-administered surveys, which included: demographics, SCD-related ED visits, clinical issues, and QoL levels. We assessed the ED use by asking for the number of SCD-related ED visits within a 6-month period. Results The self-report survey of ED visits was completed by 308 SCD patients. The median number of SCD-related ED visits within a 6-month time period (IQR) was four (2-7 visits). According to the unadjusted negative binomial model, the rate of SCD-related ED visits increased by (46, 39.3, 40, and 53.5 %) for patients with fever, skin redness with itching, swelling, and blood transfusion, respectively. Poor QoL tends to increase the rate of SCD-related ED visits. Well education and poor general health positively influenced the rate of SCD-related ED visits. Well education tends to increase the rate of SCD-related ED visits by 50.2 %. The rate of SCD-related ED visits decreased by 1.4 % for every point increase in general health. Conclusion Saudi patients with sickle cell disease reported a wide range of SCD-related ED visits. It was estimated that six of 10 SCD patients had at least three ED visits within a 6-month period. Well education and poor general health resulted in an increase in the rate of SCD-related ED visits

Evaluation of FSW Process Parameters of Dissimilar Aluminium Alloys

Friction stir welding (FSW) is relatively a new welding technology applied to join weldable Aluminum alloys and non- weldable Aluminum alloys that are widely used in many industrial applications such as aerospace, marine, automotive, and other industrial applications. In present research, dissimilar AA2024-T3 and AA6061-T6 Aluminum alloys of 3mm thickness was butt joined by using friction stir welding. The experimental study to optimize the welding parameters on tensile strength and bending test was carried out by Taguchi’s L9 orthogonal array. Experiments have been employed based on four welding parameters, namely, the tool traverse speed, rotational speed, tilt angle of tool and tool geometry. ANOVA technique and signal to Noise ratio were used to determine the most significant parameter that affects the mechanical properties of the weldment. X-ray radiographic, microstructure, microhardness tests have been conducted to demonstrate that samples subjected to the optimum welding parameters gave good quality and no defects have been observed. Keywords: FSW, aluminium alloys, dissimilar alloys, Taguchi Techniques, ANOVA, S/N ratio

Absolute Measurements for Uranium Verification Content in Radiographic Containers

Depleted Uranium (DU) is used for its very high density in civilian uses include radiation shielding in medical radiation therapy, industrial radiography equipment, containers used to transport radioactive materials. Absolute measurements have been performed for verification of uranium mass content in gamma radiography by using detector’s model developed with MCNP in nuclear safeguard inspection for these samples. Both the experimental results obtained as well as MCNP results are used to estimate the 238U mass content. The determined and the declared 238U masses values are found in an agreement with accuracy from -1.74 % to 1.80 %