Effects of additives on the cloud points of selected nonionic linear ethoxylated alcohol surfactants

Effects of various additives including inorganic salts, nonionic and ionic surfactants, water-soluble polymers and alcohols on the cloud points of three linear nonionic surfactants, Tergitol 15-S-7, Tergitol 15-S-9 and Neodol 25-7, were investigated. These surfactants are readily biodegradable and either linear primary or secondary ethoxylated alcohols. Cloud points of these surfactants were functions of their concentrations and concentrations of additives. The cloud points of nonionic surfactant mixtures lay in between the cloud points of individual component surfactants. Presence of two ionic surfactants, sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB), increased the cloud point of 1 wt% Tergitol 15-S-7 micellar solution dramatically when concentrations of ionic surfactants approaching their critical micelle concentration. Addition of water-soluble polymers decreased the cloud point, while addition of inorganic salts can either increase or decrease the cloud points. However, the effect of an alcohol additive on cloud point was dependent on its chain length or its water solubility. Interestingly, synergistic effects between sulfate or phosphate and pentanol on depression of cloud points of Tergitol 15-S-9 were discovered. A linear model predicting cloud points of Tergitol 15-S-X (X = 7, 9 and 12) surfactants and Neodol 25-X (X = 7, 9 and 12) surfactants were proposed with a correlation to logarithm of their ethylene oxide numbers.

A novel cloud-point extraction process for preconcentrating selected polycyclic aromatic hydrocarbons in aqueous solution

A novel but simple cloud-point extraction (CPE) process is developed to preconcentrate the trace of selected polycyclic aromatic hydrocarbons (PAHs) with the use of the readily biodegradable nonionic surfactant Tergitol 15-S-7 as extractant. The concentrations of PAHs, mixtures of naphthalene and phenanthrene as well as pyrene, in the spiked samples were determined with the new CPE process at ambient temperature (23 °C) followed by high performance liquid chromatography (HPLC) with fluorescence detection. More than 80% of phenanthrene and pyrene, respectively, and 96% of naphthalene initially present in the aqueous solutions with concentrations near or below their aqueous solubilities were recovered using this new CPE process. Importantly Tergitol 15-S-7 does not give any fluorometric signal to interfere with fluorescence detection of PAHs in the UV range. No special washing step is, thus, required to remove surfactant before HPLC analyses. Different experimental conditions were studied. The optimum conditions for the preconcentration and determi nation of these selected PAHs at ambient temperature have been established as the following:  (1) 3 wt % surfactant; (2) addition of 0.5 M Na2SO4; (3) 10 min for equilibration time; and (4) 3000 rpm for centrifugal speed with duration of 10 min.

A cloud of smug over outdoor education : South Park, hybrid cars and environmental morality

In an episode of South Park titled ‘Hey, People, You’ve Gotta Drive Hybrids Already’, Stan convinces townsfolk to buy hybrid cars. This reduces the rate of smog but creates a toxic cloud of ‘smug’. In this paper, I use this parody of eco-correctness to interrogate some of Outdoor Education’s environmental aims. Michel Foucault’s later work on the self, morality and governmentality is used to analyse the production of the [neo- iberal] ‘environmentally responsible citizen’. The possibilities and problems of contemporary citizenship discourse are explored in relation to findings from a longitudinal study of students undertaking a tertiary outdoor and environmental education course.

Toward higher level abstractions for cloud computing

The general idea of cloud computing is offering computational resources as scalable, on demand services accessible over the internet. However, this new realisation of on demand computing is hindered by the amount of user involvement. Currently, high level abstractions in cloud computing only exist in the form of services. In particular, there is no effective means to publish, discover and finally use required services in clouds. In response, we propose a user level abstraction on top of already available cloud abstraction layers, present its concept using the resources via web services (RVWS) framework and demonstrate its feasibility by simplifying the exposure and use of clusters, a commonly used resource in cloud computing.

Establishing trust in hybrid cloud computing environments

Establishing trust for resource sharing and collaboration has become an important issue in distributed computing environment. In this paper, we investigate the problem of establishing trust in hybrid cloud computing environments. As the scope of federated cloud computing enlarges to ubiquitous and pervasive computing, there will be a need to assess and maintain the trustworthiness of the cloud computing entities. We present a fully distributed framework that enable trust-based cloud customer and cloud service provider interactions. The framework aids a service consumer in assigning an appropriate weight to the feedback of different raters regarding a prospective service provider. Based on the framework, we developed a mechanism for controlling falsified feedback ratings from iteratively exerting trust level contamination due to falsified feedback ratings. The experimental analysis shows that the proposed framework successfully dilutes the effects of falsified feedback ratings, thereby facilitating accurate and fair assessment of the service reputations.

Prevention of information harvesting in a cloud services environment

We consider a cloud data storage involving three entities, the cloud customer, the cloud business centre which provides services, and the cloud data storage centre. Data stored in the data storage centre comes from a variety of customers and some of these customers may compete with each other in the market place or may own data which comprises confidential information about their own clients. Cloud staff have access to data in the data storage centre which could be used to steal identities or to compromise cloud customers. In this paper, we provide an efficient method of data storage which prevents staff from accessing data which can be abused as described above. We also suggest a method of securing access to data which requires more than one staff member to access it at any given time. This ensures that, in case of a dispute, a staff member always has a witness to the fact that she accessed data.

Trust ticket deployment : a notion of a data owner's trust in cloud computing

While cloud computing (CC) is a scalable model of shared infrastructure and on-demand computing, it lacks a transparent trust and security mechanism. A data owner (DO) loses control over the data outsourced to a machine in the cloud controlled and operated by a cloud service provider (CSP). This machine is at a location unknown to a data owner. This loss of control over data is further intensified with the lack of managing users' access to the data from practical cloud computing perspectives. In this paper, we introduce a new mechanism of ensuring trust and security in Software as a Service (SaaS) CC. Trust Ticket, with the supporting protocols, is our mechanism that helps a data owner in establishing a link between a CSP and a registered user. In our mechanism, a user first gets registered with a DO before receiving a Trust Ticket and a secret key from that DO. Each Trust Ticket is unique and encrypted. On completing the registration of each user, the DO apprises the CSP of the Trust Ticket. Trust Ticket and secret key are respectively for the registered user's getting accepted to the CSP and having a view of the data owner's data upon a successful verification by the CSP. We have done our experiment in Java network programming by creating an emulated cloud computing framework under the VMware ESXi 4.1 hyper visor based platform. Using the framework, we have evaluated our algorithmic protocol for Trust Ticket. We have also compared our work with prior work. Overall performance of our work is better. We argue that our proposed algorithmic protocol for Trust Ticket deployment establishes a data owner's trust. This trust is established through a data owner's control over data and a registered user, because a registered user is linked with a CSP by a data owner through Trust Ticket.

Dealing with rogue virtual machines in a cloud services environment

In current cloud services hosting solutions, various mechanisms have been developed to minimize the possibility of hosting staff from breaching security. However, while functions such as replicating and moving machines are legitimate actions in clouds, we show that there are risks in administrators being able to perform them. We describe three threat scenarios related to hosting staff on the cloud architecture and indicate how an appropriate accountability architecture can mitigate these risks in the sense that the attacks can be detected and the perpetrators identified. We identify requirements and future research and development needed to protect cloud service environments from these attacks.

Enhancing cloud computing environments using a cluster as a service

The emergence of cloud computing has caused a significant change in how IT infrastructures are provided to research and business organizations. Instead of paying for expensive hardware and incur excessive maintenance costs, it is now possible to rent the IT infrastructure of other organizations for a minimal fee. While the existence of cloud computing is new. The elements used to create clouds have been around for some time. Cloud computing systems have been made possible through the use of large-scale clusters, service-oriented architecture (SOA), Web services, and virtualization. While the idea of offering resources via Web services is commonplace in cloud computing, little attention has been paid to the clients themselves specifically, human operators. Despite that clouds host a variety of resources which in turn are accessible to a variety of clients, support for human users is minimal.

CBF : A packet filtering method for DDoS attack defense in cloud environment

Distributed Denial-of-Service attack (DDoS) is a major threat for cloud environment. Traditional defending approaches cannot be easily applied in cloud security due to their relatively low efficiency, large storage, to name a few. In view of this challenge, a Confidence-Based Filtering method, named CBF, is investigated for cloud computing environment, in this paper. Concretely speaking, the method is deployed by two periods, i.e., non-attack period and attack period. More specially, legitimate packets are collected at non-attack period, for extracting attribute pairs to generate a nominal profile. With the nominal profile, the CBF method is promoted by calculating the score of a particular packet at attack period, to determine whether to discard it or not. At last, extensive simulations are conducted to evaluate the feasibility of the CBF method. The result shows that CBF has a high scoring speed, a small storage requirement and an acceptable filtering accuracy, making it suitable for real-time filtering in cloud environment.

Cloud computing services : theoretical foundations of ethical and entrepreneurial adoption behaviour

Clouicomputing is an emerging service technology that has ethical and entrepreneurial implications. Due to technological innovations increasing the attention placed on cloud computing services, more people are focusing on the security and privacy issues determined by ethical guidelines and how the technology is evolving as an entrepreneurial service innov.ation. This paper presents a theoretical perspective on how a person adopts cloud computing. The literature on technology innovation and adoption behaviour is examined with a focus on social cognitive theory. A theoretical framework is then presented, which indicates a number of propositions to describe the intention of a person to adopt cloud computing services. The role of technology marketing capability, sustained learning and outcome expectancy are included in helping to understand the role of cloud computing applications. Suggestions for future research and practical implications are stated.

Modeling a dynamic data replication strategy to increase system availability in cloud computing environments

Failures are normal rather than exceptional in the cloud computing environments. To improve system avai-lability, replicating the popular data to multiple suitable locations is an advisable choice, as users can access the data from a nearby site. This is, however, not the case for replicas which must have a fixed number of copies on several locations. How to decide a reasonable number and right locations for replicas has become a challenge in the cloud computing. In this paper, a dynamic data replication strategy is put forward with a brief survey of replication strategy suitable for distributed computing environments. It includes: 1) analyzing and modeling the relationship between system availability and the number of replicas; 2) evaluating and identifying the popular data and triggering a replication operation when the popularity data passes a dynamic threshold; 3) calculating a suitable number of copies to meet a reasonable system byte effective rate requirement and placing replicas among data nodes in a balanced way; 4) designing the dynamic data replication algorithm in a cloud. Experimental results demonstrate the efficiency and effectiveness of the improved system brought by the proposed strategy in a cloud.