Reverse-flow integral methods for second-order supersonic flow theory,

"CM-1033."

Optimization of flocculation process and continuous filtration for sea water primary treatment filtration to reduce SDI for entree to reverse osmosis system

Today , Providing drinking water and process water is one of the major problems in most countries ; the surface water often need to be treated to achieve necessary quality, and in this way, technological and also financial difficulties cause great restrictions in operating the treatment units. Although water supply by simple and cheap systems has been one of the important objectives in most scientific and research centers in the world, still a great percent of population in developing countries, especially in rural areas, don't benefit well quality water. One of the big and available sources for providing acceptable water is sea water. There are two ways to treat sea water first evaporation and second reverse osmosis system. Nowadays R.O system has been used for desalination because of low budget price and easily to operate and maintenance. The sea water should be pretreated before R.O plants, because there is some difficulties in raw sea water that can decrease yield point of membranes in R.O system. The subject of this research may be useful in this way, and we hope to be able to achieve complete success in design and construction of useful pretreatment systems for R.O plant. One of the most important units in the sea water pretreatment plant is filtration, the conventional method for filtration is pressurized sand filters, and the subject of this research is about new filtration which is called continuous back wash sand filtration (CBWSF). The CBWSF designed and tested in this research may be used more economically with less difficulty. It consists two main parts first shell body and second central part comprising of airlift pump, raw water feeding pipe, air supply hose, backwash chamber and sand washer as well as inlet and outlet connections. The CBWSF is a continuously operating filter, i.e. the filter does not have to be taken out of operation for backwashing or cleaning. Inlet water is fed through the sand bed while the sand bed is moving downwards. The water gets filtered while the sand becomes dirty. Simultaneously, the dirty sand is cleaned in the sand washer and the suspended solids are discharged in backwash water. We analyze the behavior of CBWSF in pretreatment of sea water instead of pressurized sand filter. There is one important factor which is not suitable for R.O membranes, it is bio-fouling. This factor is defined by Silt Density Index (SDI).measured by SDI. In this research has been focused on decreasing of SDI and NTU. Based on this goal, the prototype of pretreatment had been designed and manufactured to test. The system design was done mainly by using the design fundamentals of CBWSF. The automatic backwash sand filter can be used in small and also big water supply schemes. In big water treatment plants, the units of filters perform the filtration and backwash stages separately, and in small treatment plants, the unit is usually compacted to achieve less energy consumption. The analysis of the system showed that it may be used feasibly for water treating, especially for limited population. The construction is rapid, simple and economic, and its performance is high enough because no mobile mechanical part is used in it, so it may be proposed as an effective method to improve the water quality and consequently the hygiene level in the remote places of the country.

Reverse flow and supersonic interference.

"AFOSR TN-58-625. ASTIA doc. no. AD 162 155."

Molecular epidemiological survey of rotaviruses in sewage by reverse transcriptase seminested PCR and restriction fragment length polymorphism assay

Rotavirus double-stranded RNA was detected directly in sewage treatment plant samples over a 1-year period by reverse transcription followed by PCR amplification of the VP7 gene and Southern blot hybridization. The presence of naturally occurring rotaviruses was demonstrated in 42% of raw sewage samples and in 67% of treated effluent samples, Amplified viral sequences were analyzed bg restriction enzymes. Ten different restriction profiles were characterized, most of which were found in treated effluent samples. A mixture of restriction profiles was observed in 75% of contaminated effluent samples, The profiles were compared with those obtained from human rotavirus isolates involved in infections in children from the same area (six different profiles were detected), Five identical viral sequences were detected in both environmental and clinical samples, Restriction profiles sere also compared io profiles from known genomic sequences of human and animal viruses. Both human and animal origins of rotavirus contamination of water seemed likely.

HIV Reverse Transcriptase Fidelity And Inhibition Are Modulated By Divalent Cations In A Concentration-Dependent Manner In Vitro

Human immunodeficiency virus (HIV) rapidly evolves through generation and selection of mutants that can escape drug therapy. This process is fueled, in part, by the presumably highly error prone polymerase reverse transcriptase (RT). Fidelity of polymerases can be influenced by cation co-factors. Physiologically, magnesium (Mg2+) is used as a co-factor by RT to perform catalysis, however, alternative cations including manganese (Mn2+), cobalt (Co2+), and zinc (Zn2+) can also be used. I demonstrate here that fidelity and inhibition of HIV RT can be influenced differently, in vitro, by divalent cations depending on their concentration. The reported mutation frequency for purified HIV RT in vitro is typically in the 10-4 range (per nucleotide addition), making the enzyme several-fold less accurate than most polymerases. Paradoxically, results examining HIV replication in cells indicate an error frequency that is ~10 times lower than the error rate obtained in the test tube. Here, I reconcile, at least in part, these discrepancies by showing that HIV RT fidelity in vitro is in the same range as cellular results, in physiological concentrations of free Mg2+ (~0.25 mM). At low Mg2+, mutation rates were 5-10 times lower compared to high Mg2+ conditions (5-10 mM). Alternative divalent cations also have a concentration-dependent effect on RT fidelity. Presumed promutagenic cations Mn2+ and Co2+ decreases the fidelity of RT only at elevated concentrations, and Zn2+, when present in low concentration, increases the fidelity of HIV-1 RT by ~2.5 fold compared to Mg2+. HIV-1 and HIV-2 RT inhibition by nucleoside (NRTIs) and non-nucleoside RT inhibitors (NNRTIs) in vitro is also affected by the Mg2+ concentration. NRTIs lacking 3'-OH group inhibited both enzymes less efficiently in low Mg2+ than in high Mg2+; whereas inhibition by the “translocation defective RT inhibitor”, which retains the 3ʹ-OH, was unaffected by Mg2+ concentration, suggesting that NRTIs with a 3ʹ-OH group may be more potent than other NRTIs. In contrast, NNRTIs were more effective in low vs. high Mg2+ conditions. Overall, the studies presented reveal strategies for designing novel RT inhibitors and strongly emphasize the need for studying HIV RT and RT inhibitors in physiologically relevant low Mg2+ conditions.

Corrosion of stainless steel components in seawater reverse osmosis desalination plants-investigations on adapted internal cathodic protection

Stainless steel is widely used in seawater reverse osmosis units (SWRO) for both good mechanical and corrosion resistance properties. However, many corrosion failures of stainless steel in SWRO desalination units have been reported. These failures may often be attributed to un-adapted stainless steel grade selection and/or to the particular aggressive seawater conditions in "warm" regions (high ambient temperature, severe biofouling, etc.). Cathodic protection (CP) is a well-known efficient system to prevent corrosion of metallic materials in seawater. It is successfully used in the oil and gas industry to protect carbon steel structures exposed in open-sea. However, the specific service conditions of SWRO units may seriously affect the efficiency of such anti-corrosion system (high flow rates, large stainless steel surfaces affected by biofouling, confinement limiting protective cathodic current flow, etc.). Hence, CP in SWRO units should be considered with special care and modeling appears as useful tool to assess an appropriate CP design. However, there is a clear lack of CP data that could be transposed to SWRO service conditions (i.e. stainless steel, effect of biofouling, high flow rate, etc.). From this background a Join Industry Program was initiated including laboratory exposures, field measurements in a full scale SWRO desalination plant, and modeling work using PROCOR software. The present paper reviews the main parameters affecting corrosion of stainless steel alloys in seawater reverse osmosis units. CP on specific stainless steel devices was investigated in order to assess its actual efficiency for SWRO units. Severe environmental conditions were intentionally used to promote corrosion on the tested stainless steel products in order to evaluate the efficiency of CP. The study includes a modeling work aiming at predicting and designing adapted CP protection to modeled stainless steel units. An excellent correlation between modeling work and field measurements was found.

A real-time reverse transcriptase polymerase chain reaction for detection and quantification of Vesiculovirus

Vesiculoviruses (VSV) are zoonotic viruses that cause vesicular stomatitis disease in cattle, horses and pigs, as well as sporadic human cases of acute febrile illness. Therefore, diagnosis of VSV infections by reliable laboratory techniques is important to allow a proper case management and implementation of strategies for the containment of virus spread. We show here a sensitive and reproducible real-time reverse transcriptase polymerase chain reaction (RT-PCR) for detection and quantification of VSV. The assay was evaluated with arthropods and serum samples obtained from horses, cattle and patients with acute febrile disease. The real-time RT-PCR amplified the Piry, Carajas, Alagoas and Indiana Vesiculovirus at a melting temperature 81.02 ± 0.8ºC, and the sensitivity of assay was estimated in 10 RNA copies/mL to the Piry Vesiculovirus. The viral genome has been detected in samples of horses and cattle, but not detected in human sera or arthropods. Thus, this assay allows a preliminary differential diagnosis of VSV infections.

Impaired reverse cholesterol transport and hepatic steatosis contribute to pathogenesis of high fat dietinduced hyperlipidemia in murine models

Purpose: To investigate the pathogenesis of high fat diet (HFD)-induced hyperlipidemia (HLP) in mice, rats and hamsters and to comparatively evaluate their sensitivity to HFD. Methods: Mice, rats and hamsters were fed with high-fat diet formulation (HFD, n = 8) or a control diet (control, n = 8) for 4 weeks. Changes in body weight, relative liver weight, serum lipid profile, expressions of hepatic marker gene of lipid metabolism and liver morphology were observed in three hyperlipidemic models. Results: Elevated total cholesterol (TC), triglyceride, low density lipoprotein-cholesterol (LDL-C) and high density lipoprotein-cholesterol (HDL-C) levels and body weight were observed in all hyperlipidemic animals (p < 0.05), while hepatic steatosis was manifested in rat and hamster HLP models, and increased hepatic TC level was only seen (p < 0.05) in hamster HLP model. Suppression of HMG-CoA reductase and up-regulation of lipoproteinlipase were observed in all HFD groups. Hepatic gene expression of LDLR, CYP7A1, LCAT, SR-B1, and ApoA I, which are a response to reverse cholesterol transport (RCT), were inhibited by HFD in the three models. Among these models, simultaneous suppression of HMG-CR, LCAT, LDLR and SR-BI and elevated LPL were features of the hamster model. Conclusion: As the results show, impaired RCT and excessive fat accumulation are major contributors to pathogenesis of HFD-induced murine HLP. Thus, the hamster model is more appropriate for hyperlipidemia research.

Reverse logistics in the construction industry

Reverse logistics in construction refers to the movement of products and materials from salvaged buildings to a new construction site. While there is a plethora of studies looking at various aspects of the reverse logistics chain, there is no systematic review of literature on this important subject as applied to the construction industry. Therefore, the objective of this study is to integrate the fragmented body of knowledge on reverse logistics in construction, with the aim of promoting the concept among industry stakeholders and the wider construction community. Through a qualitative meta-analysis, the study synthesises the findings of previous studies and presents some actions needed by industry stakeholders to promote this concept within the real-life context. First, the trend of research and terminology related with reverse logistics is introduced. Second, it unearths the main advantages and barriers of reverse logistics in construction while providing some suggestions to harness the advantages and mitigate these barriers. Finally, it provides a future research direction based on the review.

Culture shock and reverse culture shock: the moderating role of cultural intelligence in international students' adaptation

This study extends previous research by examining the role of cultural intelligence (CQ) in both culture shock and reverse culture shock. Specifically, this study asserts that CQ acts as a moderating mechanism that lessens the negative effects of both culture shock and reverse culture shock on psychological and sociocultural adaptation among international students. Two studies were conducted in Australia to test these assertions. Study 1 (n = 189) was participated in by new international students. An online survey was set up and disseminated. Results indicated that culture shock is significantly but negatively related to both psychological and sociocultural adaptation. In addition, results demonstrated that CQ moderates the relationship by lessening the impact of culture shock on students’ psychological and sociocultural adaptation. Study 2 (n = 123) was participated in by international students who had recently graduated and returned to their home countries. An online survey was also set up and disseminated. Results indicated that reverse culture shock is significantly but negatively related to both psychological and sociocultural adaptation. CQ also served as a moderator in lessening the impact of reverse culture shock on both forms of adaptation.

Barriers to implementing reverse logistics in South Australian construction organisations

Purpose - This paper aims to present a survey of the perceptions of the barriers to implementing reverse logistics (RL) practices in South Australian (SA) construction organisations. Despite the extensive research on forward logistics and RL, there is a paucity of studies that examine the barriers to implementing RL particularly within the Australian construction industry. This study builds on the ongoing research being undertaken by the authors, entitled “Designing for reverse logistics (DfRL) within the building life cycle: practices, drivers and barriers”, which is examining the best practices and drivers that could be used as a “road map” for developing appropriate solutions for the successful implementation of RL. Design/methodology/approach - Data were collected by utilising a triangulated data collection approach, a literature review and 49 questionnaires. The review of the literature identified 16 barriers to implementing RL. The quantitative survey data were subjected to descriptive and inferential statistics with correlation analysis to examine the relationships between different pairs of variables comprising RL’s critical barriers. Findings - The following barriers were indicated as most significant: lack of incorporation of salvaged materials by designers; regulation restrictions to usage of recovered materials and components; potential legal liabilities; higher costs; and longer-time association with deconstructing buildings. The least ranked barriers were mostly drawn from the operational and industrial categories as being: organisational lack of support for deconstruction due to incompatible design; lack of organisational support for deconstructing buildings due to higher health and safety risks; and inadequate skills and experience for deconstruction (operational). The industrial barrier was related to “higher costs of salvaged materials in comparison to virgin products”. Research limitations/implications - First, the reported findings are focussed on one study that used questionnaire surveys within the construction industry; therefore, the results may not be generalisable to other contexts. Further, studies should be conducted and extended to other industrial sectors beyond the construction industry. Second, the quantitative study (n 49) used a smaller sample, and the survey items were based on the review of the literature. Practical implications - The identified barriers could be used as a “road map” for the development of appropriate solutions for the successful implementation of RL, and to improve the environment-related decision-making processes of contractors. Originality/value - This study makes a contribution to the body of knowledge on the subject of RL within a previously unexplored SA context. In addition, the study provides some insights on the contributory effects of the barriers to the implementation of RL. It is the first work undertaken to determine the barriers to the adoption of RL within the SA construction industry.

Analysis of reverse logistics implementation practices by South Australian construction organisations

Purpose – A large number of benefits have been reported when reverse logistics (RL) is fully implemented in the construction industry. However, RL is yet to become common place in the construction sector, particularly in Australia. The particular sub-sector in which RL operates is small and weak and the remainder of the sector must embrace and accommodate it comfortably. Research is lacking on how to promoting RL in the construction industry. Very little has been done to identify the current practices that have the potential to promote RL industry-wide. The purpose of this paper is to identify the practices that work well in the sector, a strategy could be mapped out to promote RL to all stakeholders. Design/methodology/approach – In order to fill the above gap, the present study used a mixed method approach to gather and evaluate current practices and their potential to promote RL in South Australia’s construction industry. Practices that were identified using a comprehensive literature review were evaluated with a questionnaire survey and series of interviews involving construction professionals. Findings – The findings are that practices facilitating deconstruction is the most important, followed by practices facilitating the use of salvaged materials in new construction to promote RL in South Australia. Awareness of deconstruction benefits, challenges and procedures at the organisation level and facilities and services at industry level were associated with RL implementation. Availability of salvaged materials in the market was found to influence its use in new construction and as a consequence its demand. Designing for reverse logistics is another practice that could facilitate deconstruction and the onus of its promotion lies mainly with the designers. Research limitations/implications – This research was confined to one state in Australia. As such the generalisation to other states and other countries should be treated cautiously. Practical implications – The findings of this study can help inform the industry and its stakeholders on areas that they need to concentrate more on to make the South Australian construction industry a fully RL integrated one. To that end the authors propose some recommendations arising from the findings reported here. Originality/value – This study makes a contribution to the body of knowledge on reserve logistics within a previously unexplored South Australian context. In addition, the study provides valuable insights into the contribution of RL practices to the construction industry.

Hybrid threshold adaptable quantum secret sharing scheme with reverse Huffman-Fibonacci-tree coding

With prevalent attacks in communication, sharing a secret between communicating parties is an ongoing challenge. Moreover, it is important to integrate quantum solutions with classical secret sharing schemes with low computational cost for the real world use. This paper proposes a novel hybrid threshold adaptable quantum secret sharing scheme, using an m-bonacci orbital angular momentum (OAM) pump, Lagrange interpolation polynomials, and reverse Huffman-Fibonacci-tree coding. To be exact, we employ entangled states prepared by m-bonacci sequences to detect eavesdropping. Meanwhile, we encode m-bonacci sequences in Lagrange interpolation polynomials to generate the shares of a secret with reverse Huffman-Fibonacci-tree coding. The advantages of the proposed scheme is that it can detect eavesdropping without joint quantum operations, and permits secret sharing for an arbitrary but no less than threshold-value number of classical participants with much lower bandwidth. Also, in comparison with existing quantum secret sharing schemes, it still works when there are dynamic changes, such as the unavailability of some quantum channel, the arrival of new participants and the departure of participants. Finally, we provide security analysis of the new hybrid quantum secret sharing scheme and discuss its useful features for modern applications.

Drivers for adopting reverse logistics in the construction industry : a qualitative study

Purpose - The purpose of this paper is to investigate and analyse the perceptions of South Australian construction practitioners on drivers affecting the implementation of reverse logistics (RL). In this context, RL is defined as the process of moving goods from their typical final destination for the purpose of capturing value or ensuring proper disposal.

Design/methodology/approach - Semi-structured interviews were conducted with eight practitioners to collect data and the interview transcripts were analysed using the NVivo (version 10) package. Cluster analysis was used to cross-validate the findings and provide an in-depth insight into the findings.

Findings - The findings indicate that most of the drivers identified in earlier research are relevant for the construction industry. In addition, the study identified some new drivers that are categorised as "targeted demands by an exclusive clientele". These drivers were found to be complementary to the economic, environmental and social drivers as previously conceptualised. In addition, a set of factors affecting the strength of drivers that had been overlooked in previous studies emanated from the interview analysis. These include the type of project and the attributes of clients, both of which strongly affect the drivers of RL implementation in construction.

Research limitations/implications - The major limitations are the relatively small size of the sample of interviewees and having interviewees from one geographic area with specific socio-economic characteristics.

Practical implications - The identified drivers and the clustering of RL themes could be used by practitioners as a "road map" for the development of appropriate solutions to successfully promote RL within the construction industry. Organisational energies could thus be channelled towards the drivers that need the most improvement.

Originality/value - The study contributes to this research sphere by employing cluster analysis to customise and contextualise the drivers that were previously identified. The study goes beyond the extant literature by discovering the prominent effects of these drivers on the impact of targeted demands by an exclusive clientele. This could be of great value in terms of creating avenues for future investigations on the topic.