Electrospray ion beam deposition and preparation of model molecular solar cells surfaces

Studying the fundamental science of surface science of dye sensitised solar cells requires placing complex molecules on surfaces in an ultra-high vacuum. Since most dye molecules are fragile and non-volatile to be deposited by thermal evaporation or sublimation technique, electrospray deposition was therefore explored as an alternative method. This thesis aims to work on developing the electrospray deposition technique to obtain high-quality monolayers in situ in high vacuum environments. Image charge detection mass spectrometry (CDMS) has been used to measure the speed and charge distributions of molecular ions. Image charge drift tube measurements formed large clusters giving strong transient signals with a narrow velocity distribution of cluster sizes ranging from 300 ms−1 and 330 ms−1. The charge-to-speed relationship showed fitting with a 1/v2, meaning that all clusters have constant kinetic energy. In the case of the small clusters or individual molecular ions travelling through the drift tube, advanced electronics are required to see the weak signals hidden in the background noise. The electrostatic ion deflector experiments, highlighting the capabilities of bending the ion beam in order to work towards separating two components of the beam, showed the formation of large clusters in the beam. These clusters have required a higher voltage in order to be deflected by the same amount based on SIMION simulations and a smooth range of charge distributions. Small molecular ions are worth studying in the future - via the discovery of low voltage range since these deflection experiments have concentrated on the high voltage regime. In the second section, the XPS measurements of defocussing experiments showed an incapability of the Einzel lens to diverge the beam over a large area on the sample, especially when the SIMION simulation achieved this. As well as, the defocussing experiment using a long tube exhibited the success of the Einzel lens to spread the beam over the entire sample. In the last section, AFM and optical images displayed the deposition of graphene oxide successfully with heterogeneous deposition coverage across the surface. Dye-sensitisers adsorbed onto rutile TiO2 (110) were deposited in situ in UHV using electrospray deposition. Adsorption geometries and determining the dispersion of these molecules with this titanium surface were investigated using X-ray photoemission spectroscopy (XPS). The results of O 1s photoemission in the monolayer coverages showed that dye complexes bind onto TiO2 (110) by deprotonation of the carboxylic acid and phosphonic acid groups so that their oxygen atoms bond to titanium atoms of the substrate. Photoemission of C 1s, together with N 1s, indicated that the molecule is intact on the surface

Electrospray ion beam deposition and preparation of model molecular solar cells surfaces

Studying the fundamental science of surface science of dye sensitised solar cells requires placing complex molecules on surfaces in an ultra-high vacuum. Since most dye molecules are fragile and non-volatile to be deposited by thermal evaporation or sublimation technique, electrospray deposition was therefore explored as an alternative method. This thesis aims to work on developing the electrospray deposition technique to obtain high-quality monolayers in situ in high vacuum environments. Image charge detection mass spectrometry (CDMS) has been used to measure the speed and charge distributions of molecular ions. Image charge drift tube measurements formed large clusters giving strong transient signals with a narrow velocity distribution of cluster sizes ranging from 300 ms−1 and 330 ms−1. The charge-to-speed relationship showed fitting with a 1/v2, meaning that all clusters have constant kinetic energy. In the case of the small clusters or individual molecular ions travelling through the drift tube, advanced electronics are required to see the weak signals hidden in the background noise. The electrostatic ion deflector experiments, highlighting the capabilities of bending the ion beam in order to work towards separating two components of the beam, showed the formation of large clusters in the beam. These clusters have required a higher voltage in order to be deflected by the same amount based on SIMION simulations and a smooth range of charge distributions. Small molecular ions are worth studying in the future - via the discovery of low voltage range since these deflection experiments have concentrated on the high voltage regime. In the second section, the XPS measurements of defocussing experiments showed an incapability of the Einzel lens to diverge the beam over a large area on the sample, especially when the SIMION simulation achieved this. As well as, the defocussing experiment using a long tube exhibited the success of the Einzel lens to spread the beam over the entire sample. In the last section, AFM and optical images displayed the deposition of graphene oxide successfully with heterogeneous deposition coverage across the surface. Dye-sensitisers adsorbed onto rutile TiO2 (110) were deposited in situ in UHV using electrospray deposition. Adsorption geometries and determining the dispersion of these molecules with this titanium surface were investigated using X-ray photoemission spectroscopy (XPS). The results of O 1s photoemission in the monolayer coverages showed that dye complexes bind onto TiO2 (110) by deprotonation of the carboxylic acid and phosphonic acid groups so that their oxygen atoms bond to titanium atoms of the substrate. Photoemission of C 1s, together with N 1s, indicated that the molecule is intact on the surface

Knowledge and Practice of Adult Population Regarding Hepatitis B Virus (HBV) in Riyadh, Saudi Arabia

Background: Hepatitis B virus (HBV) Infection is a serious worldwide community health problem. HBV is the 10th leading reason of global death. Tentatively, hepatitis B is a serious infection activated by HBV, which attacks the liver and can cause both acute and chronic disease. Aim: To explore the adult population’s Knowledge and Practice regarding Hepatitis B Virus (HBV) in Riyadh, Saudi Arabia. Design: To achieve the aim of the current study a descriptive correlation design was used. Method: 402 adult Saudi male and female were recruited in the current study from different regions in Riyadh; data was collected by a questionnaire developed in English by the researchers then translated to Arabic, the tool consisted of 3 sections; section 1: Contained questions related to socio-demographic and biomedical data. Section2: contained 17 questions for knowledge assessment. Section3: contained 10 questions for practice assessment. Results: The study results showed that the total knowledge mean score  x̄ + SD was 22.23 + 4.22, the total practice  mean score  x̄ + SD was 7.43 + 4.19 and revealed that there was a statistically significant differences between total knowledge score and total practice score with  r = 0.113 and P = 0.023 and also showed a statistical significant differences between the level of education with knowledge r = 0.12 and P = 0.015 however, there is no statistical significant differences between the level of education and practice r =-0.04 and p=0.94. Conclusion: The knowledge regarding HBV among Saudi population in Riyadh was fair while the practice was poor, which indicated the need of more awareness and education campaigns regarding the good practice about HBV. Keywords: Hepatitis B virus (HBV), Knowledge, Practice

Enhancing graph routing algorithm of industrial wireless sensor networks using the covariance-matrix adaptation evolution strategy

The emergence of the Industrial Internet of Things (IIoT) has accelerated the adoption of Industrial Wireless Sensor Networks (IWSNs) for numerous applications. Effective communication in such applications requires reduced end-to-end transmission time, balanced energy consumption and increased communication reliability. Graph routing, the main routing method in IWSNs, has a significant impact on achieving effective communication in terms of satisfying these requirements. Graph routing algorithms involve applying the first-path available approach and using path redundancy to transmit data packets from a source sensor node to the gateway. However, this approach can affect end-to-end transmission time by creating conflicts among transmissions involving a common sensor node and promoting imbalanced energy consumption due to centralised management. The characteristics and requirements of these networks encounter further complications due to the need to find the best path on the basis of the requirements of IWSNs to overcome these challenges rather than using the available first-path. Such a requirement affects the network performance and prolongs the network lifetime. To address this problem, we adopt a Covariance-Matrix Adaptation Evolution Strategy (CMA-ES) to create and select the graph paths. Firstly, this article proposes three best single-objective graph routing paths according to the IWSN requirements that this research focused on. The sensor nodes select best paths based on three objective functions of CMA-ES: the best Path based on Distance (PODis), the best Path based on residual Energy (POEng) and the best Path based on End-to-End transmission time (POE2E). Secondly, to enhance energy consumption balance and achieve a balance among IWSN requirements, we adapt the CMA-ES to select the best path with multiple-objectives, otherwise known as the Best Path of Graph Routing with a CMA-ES (BPGR-ES). A simulation using MATALB with different configurations and parameters is applied to evaluate the enhanced graph routing algorithms. Furthermore, the performance of PODis, POEng, POE2E and BPGR-ES is compared with existing state-of-the-art graph routing algorithms. The simulation results reveal that the BPGR-ES algorithm achieved 87.53% more balanced energy consumption among sensor nodes in the network compared to other algorithms, and the delivery of data packets of BPGR-ES reached 99.86%, indicating more reliable communication

Effect of Unequal Clustering Algorithms in WirelessHART networks

The use of Graph Routing in Wireless Highway Addressable Remote Transducer (WirelessHART) networks offers the benefit of increased reliability of communications because of path redundancy and multi-hop network paths. Nonetheless, Graph Routing in a WirelessHART network creates a hotspot challenge resulting from unbalanced energy consumption. This paper proposes the use of unequal clustering algorithms based on Graph Routing in WirelessHART networks to help with balancing energy consumption, maximizing reliability, and reducing the number of hops in the network. Graph Routing is compared with pre-set and probabilistic unequal clustering algorithms in terms of energy consumption, packet delivery ratio, throughput and average end-to-end delay. A simulation test reveals that Graph Routing has improved energy consumption, throughput and reduced average end-to-end delay when conducted using probabilistic unequal clustering algorithms. However, there is no significant change in the packet delivery ratio, as most packets reach their destination successfully anyway

A Secure and Robust Image Hashing Scheme Using Gaussian Pyramids

Image hash is an alternative to cryptographic hash functions for checking integrity of digital images. Compared to cryptographic hash functions, an image hash or a Perceptual Hash Function (PHF) is resilient to content preserving distortions and sensitive to malicious tampering. In this paper, a robust and secure image hashing technique using a Gaussian pyramid is proposed. A Gaussian pyramid decomposes an image into different resolution levels which can be utilized to obtain robust and compact hash features. These stable features have been utilized in the proposed work to construct a secure and robust image hash. The proposed scheme uses Laplacian of Gaussian (LOG) and disk filters to filter the low-resolution Gaussian decomposed image. The filtered images are then subtracted and their difference is used as a hash. To make the hash secure, a key is introduced before feature extraction, thus making the entire feature space random. The proposed hashing scheme has been evaluated through a number of experiments involving cases of non-malicious distortions and malicious tampering. Experimental results reveal that the proposed hashing scheme is robust against non-malicious distortions and is sensitive to detect minute malicious tampering. Moreover, False Positive Probability (FPP) and False Negative Probability (FNP) results demonstrate the effectiveness of the proposed scheme when compared to state-of-the-art image hashing algorithms proposed in the literature

Quality of Life of Patients with Chronic Kidney Disease

This study aimed at exploring the assessment of Quality of Life (QOL) in patients with Chronic Kidney Disease (CKD), and aiming at assessing the QOL of patients with stages 1–5 Chronic Kidney Disease CKD on conservative treatment in order to identify a possible association between Quality Of Life QOL and progression of kidney insufficiency. The results were compared with those obtained for patients on hemodialysis. Sociodemographic, clinical and laboratory data were also evaluated. And the study concluded that research efforts have expanded significantly to determine the state of pediatric CKD patient HRQOL and the factors that impact HRQOL across all stages of CKD and all modalities of renal replacement therapy. Data from all studies suggest that children with a renal transplant fare better with respect to HRQOL than those receiving dialysis

Squint Among Adult Population in Hail City, Saudi Arabia

Background: Strabismus, also known as crossed eyes, is a condition in which the eyes do not properly align with each other when looking at an object. If present during a large part of childhood, it may result in amblyopia. If onset is during adulthood, it is more likely to result in double vision. Objective: The aim of the study was to estimate the prevalence of squint, types and treatment characteristics in the studied adults in Hail city, Saudi Arabia. Methods: A cross-sectional study conducted in Hail city, Saudi Arabia. The study included 294 participants; 95 male and 199 female adults aged >20 years. The study period was from 1 January to 30 April 2018. Data collected by personal interview using a pre-designed questionnaire, which distributed among the participants to be self-reported. Results: The prevalence of squint among the studied population was 9.9%. it was more common in females than males. Squint was right sided in 24.1% of the cases, left sided in 51.7% and in both eyes in 24.1% of the studied cases. About half (44.8%) of cases had inward squint (esotropia) and 10.3% outward squint (exsotropia), 24.1% of the cases had Intermittent squint and 6.9% had permanent squint. Most (55.2%) of squint cases use glasses and 34.5% of cases squint affected their visual acuity. In 6.9%, squint causes psychological troubles. As regards treatment, 20.7% received medical treatment and 17.2% received surgical treatment but 62.1% do not seek medical care. Only 10.3% of cases completely cured and 13.8% had recurrence. There was insignificant relation with age, sex, education, squint in parents, chronic diseases, consanguinity or hereditary diseases (P>0.05). Conclusion: in this study, the prevalence of squint in the adult participants in Hail city, Saudi Arabia was 9.9% but 62.1% do not seek medical care. After treatment, only 10.3% of cases completely cured and 13.8% had recurrence. Health education of the public about importance of early treatment is highly recommended. Keywords: Squint; strabismus; adult population; prevalence; types; Hail; Saudi Arabia

A Weighted Minimum Redundancy Maximum Relevance Technique for Ransomware Early Detection in Industrial IoT

Ransomware attacks against Industrial Internet of Things (IIoT) have catastrophic consequences not only to the targeted infrastructure, but also the services provided to the public. By encrypting the operational data, the ransomware attacks can disrupt the normal operations, which represents a serious problem for industrial systems. Ransomware employs several avoidance techniques, such as packing, obfuscation, noise insertion, irrelevant and redundant system call injection, to deceive the security measures and make both static and dynamic analysis more difficult. In this paper, a Weighted minimum Redundancy maximum Relevance (WmRmR) technique was proposed for better feature significance estimation in the data captured during the early stages of ransomware attacks. The technique combines an enhanced mRMR (EmRmR) with the Term Frequency-Inverse Document Frequency (TF-IDF) so that it can filter out the runtime noisy behavior based on the weights calculated by the TF-IDF. The proposed technique has the capability to assess whether a feature in the relevant set is important or not. It has low-dimensional complexity and a smaller number of evaluations compared to the original mRmR method. The TF-IDF was used to evaluate the weights of the features generated by the EmRmR algorithm. Then, an inclusive entropy-based refinement method was used to decrease the size of the extracted data by identifying the system calls with strong behavioral indication. After extensive experimentation, the proposed technique has shown to be effective for ransomware early detection with low-complexity and few false-positive rates. To evaluate the proposed technique, we compared it with existing behavioral detection methods