Sorption and activation of hydrocarbons by molecular sieves

Substantial progress has been made recently in the understanding of sorption and activation of alkanes. This progress reflects the emergence of new theoretical and experimental results, leading to a more quantitative picture of the elementary steps involved in the ordering of alkanes in molecular sieves and their chemical interaction with the acid site. Conversion of n-alkanes over various zeolites is now well understood to depend mainly upon the concentration of reactants sorbed. The sorption enthalpy and entropy of these molecules are linearly related and this relationship is characteristic of a particular molecular sieve (compensation effect). The interfacial chemistry that alkanes and alkenes undergo involves ionic species only in their transition state, whereas the stable intermediates are covalently bound. This leads to a description of the chemical transformations that resemble nucleophilic and electrophilic substitutions

The effect of addition of a third component on the behaviour of the lithium doped magnesium catalysts for the oxidative dehydrogenation of ethane

The oxidative dehydrogenation of ethane was studied with the use of promoted Li/MgO catalysts at temperatures of 600¿650°C. The addition of known promoters, cobalt and tin, gave a slight Increase In activity but a strong decrease in selectivity to ethylene under the conditions used. The addition of sodium improved the selectivity to ethylene and suppressed the formation of carbon monoxide. Using a feed of 12 vol% ethane and 6 vol% oxygen, the U/Na/MgO catalyst with 3.2wt% sodium showed a selectivity of 86 % to ethylene at 38 % conversion of ethane; the Li/MgO catalyst showed a selectivity of 80 % at similar conversions Thermal Investigations of the Li/Na/MgO catalyst showed that an eutectic melt of LINaCO3 is formed at 490°C; the existence of this molten phase is probably the cause of the Increased selectivity

Challenges and Strategies for Providing Effective Antenatal Education Services in Oman’s Public Healthcare System: Perspectives of service providers and pregnant women

Objectives: Globally, maternal mortality is considered a critical healthcare issue because statistics consistently show that many avoidable deaths and injuries occur during pregnancy and childbirth. The aim of this research was to explore the challenges to quality antenatal education from the perspective of both the service providers and the pregnant women. Methods: This qualitative study was carried out on 30 participants who were selected using purposive sampling technique. Data was collected through in-depth interviews and field notes and analyzed manually using thematic analysis. Results: The service providers identified their challenges as lack of consultation room and designated space for health education, work overload, time constraints, under-staffing, lack of educational materials, language barriers, lack of authority and negative attitude. The pregnant women identified lack of focus on women’s needs, superficial antenatal education, overcrowding, lack of educational facilities, use of medical jargon and unprofessional staff attitude towards women as key barriers to quality service. The remedies included improved staffing levels, designated space for antenatal education, expanded educational activities, continuing education for caregivers, establishing midwife-led units, focused antenatal education and improved communication between providers and the users. Conclusion: Based on the results, both health care service providers and pregnant women experienced significant barriers that hindered them from providing and accessing quality antenatal education services respectively. Therefore, policymakers, health planners and hospital administrators should remove these barriers and integrate some of the recommendations to promote better health outcomes. Keywords: Antenatal Education; Challenges; Strategies; Health Care Providers; Pregnant Women; Oman

Oxidative Conversion of Hexane to Olefins-Influence of Plasma and Catalyst on Reaction Pathways

An integrated plasma-Li/MgO system is efficient for the oxidative conversion of hexane. In comparison to the Li/MgO catalytic system, it brings considerable improvements in the yields of light olefins (C 2 = –C 5 = ) at relatively low temperatures indicating synergy from combination of plasma and catalyst. The study on the influence of temperature on the performance of the integrated plasma-Li/MgO system shows dominancy of plasma chemistry at the lower temperature (500°C), while contribution from the catalyst both in hexane activation and in enhancing olefin formation becomes significant at the higher temperature (600°C). At 500°C significant amount of acetylene formation is observed. This is minimized at 600°C at oxygen depleting condition

RAID-2: Design and implementation of a large scale disk array controller

We describe the implementation of a large scale disk array controller and subsystem incorporating over 100 high performance 3.5 inch disk drives. It is designed to provide 40 MB/s sustained performance and 40 GB capacity in three 19 inch racks. The array controller forms an integral part of a file server that attaches to a Gb/s local area network. The controller implements a high bandwidth interconnect between an interleaved memory, an XOR calculation engine, the network interface (HIPPI), and the disk interfaces (SCSI). The system is now functionally operational, and we are tuning its performance. We review the design decisions, history, and lessons learned from this three year university implementation effort to construct a truly large scale system assembly

Challenges and Strategies for Building and Maintaining Effective Preceptor-Preceptee Relationships among Nurses

Objectives: This study aimed to determine the challenges encountered and strategies used by nurse preceptors to build effective professional relationships during the preceptorship of final year nursing students. Methods: This study was conducted in November 2012 at the College of Nursing in Sultan Qaboos University, Muscat, Oman. A qualitative research design consisting of focus group discussions was used to investigate the challenges that preceptors encounter and the strategies that they use to build effective relationships with preceptees. A total of 21 preceptors from Sultan Qaboos University Hospital participated in the study as part of a training workshop for nurse preceptors. The interviews were audio recorded, transcribed verbatim and thematically analysed. Results: The main challenges faced by preceptors included discrepancies in applying theory to practice; lack of trust; lack of time, and perceived lack of knowledge. The effective strategies identified by the preceptors to be used in building a healthy preceptor-preceptee relationship were proper orientation; effective communication; preparation for complex situations; appreciation and acknowledgment; positive feedback; assurance of support; spending time together; knowing preceptors personally; giving breaks, and encouraging self-commitment. Conclusion: Preceptors should be encouraged to identify challenges that hinder the building of effective relationships with preceptees early during their preceptorship. The incorporation of appropriate and evidenced-based strategies, such as those identified in this study, can transform the preceptorship experience into one that is fulfilling for both preceptors and preceptees. This may lead to greater job satisfaction, personal and professional growth as well as higher self-esteem levels for preceptors and the realisation of clinical objectives for preceptees

GenSelfDiff-HIS: Generative Self-Supervision Using Diffusion for Histopathological Image Segmentation

Histopathological image segmentation is a laborious and time-intensive task, often requiring analysis from experienced pathologists for accurate examinations. To reduce this burden, supervised machine-learning approaches have been adopted using large-scale annotated datasets for histopathological image analysis. However, in several scenarios, the availability of large-scale annotated data is a bottleneck while training such models. Self-supervised learning (SSL) is an alternative paradigm that provides some respite by constructing models utilizing only the unannotated data which is often abundant. The basic idea of SSL is to train a network to perform one or many pseudo or pretext tasks on unannotated data and use it subsequently as the basis for a variety of downstream tasks. It is seen that the success of SSL depends critically on the considered pretext task. While there have been many efforts in designing pretext tasks for classification problems, there haven't been many attempts on SSL for histopathological segmentation. Motivated by this, we propose an SSL approach for segmenting histopathological images via generative diffusion models in this paper. Our method is based on the observation that diffusion models effectively solve an image-to-image translation task akin to a segmentation task. Hence, we propose generative diffusion as the pretext task for histopathological image segmentation. We also propose a multi-loss function-based fine-tuning for the downstream task. We validate our method using several metrics on two publically available datasets along with a newly proposed head and neck (HN) cancer dataset containing hematoxylin and eosin (H\&E) stained images along with annotations. Codes will be made public at https://github.com/PurmaVishnuVardhanReddy/GenSelfDiff-HIS.git

Renewable fuel production from hydropyrolysis of residual biomass using molybdenum carbide-based catalysts: An analytical Py-GC/MS investigation

Fast hydropyrolysis of lignocellulosic biomass was studied by using an analytical pyrolyzer coupled with a gas chromatography/mass spectrometry set-up (Py-GC/MS). Under pure H2 stream, Canadian pinewood was rapidly heated up to 500 °C and the generated vapors passed through a catalytic bed at 500 °C. Experiments were carried out in order to compare the catalytic performance of MoC/Al2O3 catalyst to a reference catalyst based on noble metal (1.5 wt.% Pt/Al2O3). The effect of different supports (Al2O3, ZrO2 and MgO) on the carbide performance and product formation was investigated. The results showed that the performance of MoC/Al2O3 was similar to that of 1.5 wt.% Pt/Al2O3. Both of them deoxygenated the hydropyrolysis vapors and led exclusively to hydrocarbons formation. However, the proportion of aliphatic and aromatic hydrocarbons was different: MoC/Al2O3 catalyst produced more aliphatics (57%) than the Pt catalyst. The supports have demonstrated influence on the product distribution. Acidity of the support seems to play an important role in the deoxygenation of the vapors. While there was complete removal of oxygen when MoC/Al2O3 and MoC/ZrO2 were used, the same did not take place for the more basic MoC/MgO catalyst