MODELING OF CONSOLIDATION AND FLOW OF GRANULAR MATERIAL UNDER VARYING CONDITIONS

Granular materials are ubiquitous. They are widely used in many natural and man-made processes such as formation of lunar regolith, dunes and beach sand, as well as processes in pharmaceutical, chemical, and construction industries. Despite their clear industrial relevance, a fundamental understanding of most of the phenomena that involve granular materials in the chemical industry is lacking. Recently, it has been found that cyclic variation of the temperature of a granular bed can cause static particle beds to consolidate (increase their packing fraction) over time due to thermo-mechanical coupling. We employ experimental techniques and numerical simulations, using the thermal particle dynamics method (TPD), to study this phenomenon. In order to simulate many natural phenomena such as lunar regolith formation, one needs to determine a simulation depth of the bed which will yield realistic results yet be manageable computationally. Here we use penetration theory to estimate the required simulation bed height. Lateral periodic boundary conditions are used in our simulations to show that consolidation still occurs during vertical heating even in the absence of confining side walls. Granular flows in which shearing plays a key role are prevalent in natural and industrial applications and understanding their behavior and flow characteristics is of considerable importance. Nevertheless, difficulties in making accurate experimental measurements, complexities involved in doing bulk characterization, and the non-linear nature of interparticle interactions have made development and testing of theoretical models extremely challenging. For this reason, the discrete element method (DEM) is often used as the gold standard for comparison to continuum-level theories of granular material flows. Due to the fact that this modeling approach is derived from first-principle constructs -- like contact mechanics -- its use in lieu of experimentation is reasonably wide-spread and is becoming a staple even in industrial practice. In this work, we explore various aspects of quantitative validation of DEM simulations using detailed measurements of simple, well-characterized flows that allow us to examine the effect of rough surfaces, rotational rates, collisional and frictional force models on granular flow using different devices. Experimentally, we use digital particle tracking velocimetry (DPTV) to obtain velocity, solids fractions, and granular temperature profiles. Computationally, we compare the results obtained using different contact mechanics force laws to those from experimental measurements and perform sensitivity analyses on device and particle geometry as well as material properties employed. In general, the frictional force models range from pragmatic linear techniques to rigorously more complex (nonlinear) contact mechanics inspired routines. Here, we examine both force models to compare with the experimental measurements. In addition, we examine the robustness of these observations to both particle materials properties as well as systemic variables (such as total system solids fraction)

Knowledge and Attitude of Oral Health Professionals in the Management of Avulsed Teeth

Objectives: The purpose of this study is to assess the knowledge and to compare the attitude and management of tooth avulsion between the general dentist and the specialist all with dental interns.  Materials and Methods:16-point questionnaires have been developed to a similar study and have been validated by a group of specialist.  The first part of the survey contained demographic data. The second part consisted of eight questions checking dentists’ knowledge on the treatment of avulsed teeth. All in which took part in Saudi Arabia, Riyadh and covered 311 dentists. Data were analyzed with SPSS program version 21Results: 583 questionnaires have been distributed and a total of 311 were collected. Which consisted 53.34% of distributed surveys. Almost two-third (219) of the surveyed populations have never treated any patient with dental avulsion. Amongst those who had such experience, the majority treated at least one case (35.9%), there were also 22 (23.9%) dentist who treated more than 5 avulsed teeth. 25 of 311 dentist have never received education or training in the management of tooth avulsion. Conclusion: there is a need to familiarize oral health professions with the needed knowledge and management of avulsion through lectures and proper training. Keywords: Avulsion; knowledge; management; oral professional; denta

Overview of the Parents’ Knowledge, Attitude and Practice of Children Vaccinations: A Systematic Review

Background: It is the parents' responsibility to vaccinate their children. As a result, parents' attitudes, knowledge, and beliefs about vaccination are critical because they influence their activities toward timely and full immunization.  Objectives: This systematic review comprehensively investigated the recently published literature on parents’ knowledge regarding children’s vaccination.  Methods: PubMed, SCOPUS, Web of Science, Science Direct, and Google Scholar were systematically searched to include the relevant literature. Rayyan QRCI was used throughout this systematic approach. Results & interpretation: This review included twenty-four studies with a total of 13082 parents, and 70.9% were mothers. Knowledge level about children’s vaccination among parents was significantly related to their fathers' age, education level, women's employment status, and family type. Younger mothers were found to have a higher level of expertise. Good knowledge levels and positive attitudes towards the seasonal influenza vaccine were reported. Good knowledge with caution was reported among parents regarding COVID-19 vaccination. The knowledge about HPV infection and vaccination: All of them reported low vaccination rates and willingness to vaccinate their children. The findings of our study highlight the significance of parental understanding of vaccinations and immunization. Health officials should make additional efforts to promote the benefits of vaccination while emphasizing the risks of non- or late pediatric immunization

Pharmacological Inhibition of Caspase and Calpain Proteases: A Novel Strategy to Enhance the Homing Responses of Cord Blood HSPCs during Expansion

Background: Expansion of hematopoietic stem/progenitor cells (HSPCs) is a well-known strategy employed to facilitate the transplantation outcome. We have previously shown that the prevention of apoptosis by the inhibition of cysteine proteases, caspase and calpain played an important role in the expansion and engraftment of cord blood (CB) derived HSPCs. We hypothesize that these protease inhibitors might have maneuvered the adhesive and migratory properties of the cells rendering them to be retained in the bone marrow for sustained engraftment. The current study was aimed to investigate the mechanism of the homing responses of CB cells during expansion. Methodology/Principal Findings: CB derived CD34 + cells were expanded using a combination of growth factors with and without Caspase inhibitor-zVADfmk or Calpain 1 inhibitor- zLLYfmk. The cells were analyzed for the expression of homingrelated molecules. In vitro adhesive/migratory interactions and actin polymerization dynamics of HSPCs were assessed. In vivo homing assays were carried out in NOD/SCID mice to corroborate these observations. We observed that the presence of zVADfmk or zLLYfmk (inhibitors) caused the functional up regulation of CXCR4, integrins, and adhesion molecules, reflecting in a higher migration and adhesive interactions in vitro. The enhanced actin polymerization and the RhoGTPase protein expression complemented these observations. Furthermore, in vivo experiments showed a significantly enhanced homing to the bone marrow of NOD/SCID mice

.The Criminal Liability of Ministers in Kuwait

The criminal responsibility of a minister is provided for in Article 132 of the Kuwaiti constitution, by giving the parliament the power to issue a law for the trial of ministers. This law will define the potential ministerial offences; the procedures to be followed as well as the court authorised to undertake the trial of ministers. The aim of this study is to investigate the constitutionality and applicability of the law of trial of ministers in Kuwait, and the extent to which this law has been influenced by the laws of criminal trial ofministers in other jurisdictions in particular French and Egyptian Law.To reach that end this study will first discuss the growth and development of criminal responsibility in both the Kuwaiti law and the other similar jurisdictions. The study will then discuss the ministerial crime, before investigating the p~ocedures to make a criminal case against a minister. Then the body authorised with the investigation in case a minister commits a crime while on duty will be discussed, besides the formation of the ministerial court and the authority of this court.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Importance of early precautionary actions in avoiding the spread of COVID-19: Saudi Arabia as an Example

Late in 2019, several cases of infection with a new strain of coronavirus were reported in China. This new strain was later officially named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by the World Health Organization (WHO). This new virus (SARS-CoV2-) mainly affects the respiratory system and causes coronavirus disease 2019 (COVID-19). The first case of COVID-19 was reported to the WHO on December 31st, 2019, and the virus has spread dramatically in many countries worldwide. On March 11th, 2020, the WHO declared that COVID-19 had affected most of the world, and many deaths were linked to COVID-19. Unfortunately, there is no available treatment for COVID-19, and there is no available vaccine against SARS-CoV-2. Thus, preventive methods are the only way to limit the spread of the virus. Preventive actions have been taken by many countries, such as travel bans, closing borders and working from home. Saudi Arabia was one of the countries that took very early precautionary actions in the belief that these actions are the best way to fight the virus. Therefore, we present the actions that were taken by the Kingdom of Saudi Arabia to fight the new viral pandemic

Liquid-Liquid equilibria of ternary mixtures of alkane (C8 or C12) + thiophene + three methylimidazolium dicyanamide (DCA)-based ionic liquids

It is becoming eminent in the oil refining industry to diminish the sulfur content in their fuels to limit the harmful emissions of sulfur oxides (SOx) to public health and the environment. Liquid–liquid extractions of thiophene from paraffin compounds have been investigated using 1-ethyl-3-methylimidazolium dicyanamide [emim][DCA], 1‑butyl‑3-methylimidazolium dicyanamide [bmim][DCA], and 1-benzyl-3-methylimidazolium dicyanamide [bzmim][DCA] ionic liquids at 313.15 K and an atmospheric pressure of 101.3 kPa. Liquid–liquid equilibrium data for the three ternary systems: {iso-octane (1) + thiophene (2) + [emim][DCA] or [bmim][DCA] (3)} and {tetradecane (1) + thiophene (2) + [bzmim][DCA] (3)} were determined. In addition, distribution ratios and selectivity values were computed and compared for these systems to evaluate the desulfurization competence (aptitude). The thermodynamic nonrandom two-liquid (NRTL) model was used to correlate the experimental data