Environmental impact categories of hydrogen and ammonia driven transoceanic maritime vehicles: A comparative evaluation

In this study, carbon-free fuels -ammonia and hydrogen-are proposed to replace heavy fuel oils in the engines of maritime transportation vehicles. Also, it is proposed to use hydrogen and ammonia as dual fuels to quantify the reduction potential of greenhouse gas emissions. An environmental impact assessment of transoceanic tanker and transoceanic freight ship is implemented to explore the impacts of fuel substituting on the environment. In the life cycle analyses, the complete transport life cycle is taken into account from manufacture of transoceanic freight ship and tanker to production, transportation and utilization of hydrogen and ammonia in the maritime vehicles. Several hydrogen and ammonia production routes ranging from municipal waste to geothermal options are considered to comparatively evaluate environmentally benign methods. Besides global warming potential, environmental impact categories of marine sediment ecotoxicity and marine aquatic ecotoxicity are also selected in order to examine the diverse effects on marine environment. Being carbon-neutral fuels, ammonia and hydrogen, yield significantly minor global warming impacts during operation. The ecotoxicity impacts on maritime environment vary based on the production route of hydrogen and ammonia. The results imply that even hydrogen and ammonia are utilized as dual fuels in the engines, the global warming potential is quite lower in comparison with heavy fuel oil driven transoceanic tankers. Geothermal energy sourced hydrogen and ammonia fuelled transoceanic tankers release about 0.98 g and 1.65 g CO₂ eq. per tonne-kilometer, respectively whereas current conventional heavy fuel oil tanker releases about 5.33 g/tonne-kilometer CO₂ eq. greenhouse gas emissions.     

Wind-driven ventilation improvement with plan typology alteration: A CFD case study of traditional Turkish architecture

Aligned with achieving the goal of net-zero buildings, the implementation of energy-saving techniques in minimizing energy demands is proving more vital than at any time. As practical and economic options, passive strategies in ventilation developed over thousands of years have shown great potential for the reduction of residential energy demands, which are often underestimated in modern building’s construction. In particular, as a cost-effective passive strategy, wind-driven ventilation via windows has huge potential in the enhancement of the indoor air quality (IAQ) of buildings while simultaneously reducing their cooling load. This study aims to investigate the functionality and applicability of a common historical Turkish architectural element called “Cumba” to improve the wind-driven ventilation in modern buildings. A case study building with an archetypal plan and parameters was defined as a result of a survey over 111 existing traditional samples across Turkey. Buildings with and without Cumba were compared in different scenarios by the development of a validated CFD microclimate model. The results of simulations clearly demonstrate that Cumba can enhance the room’s ventilation rate by more than two times while harvesting wind from different directions. It was also found that a flexible window opening strategy can help to increase the mean ventilation rate by 276%. Moreover, the room’s mean air velocity and ventilation rate could be adjusted to a broad range of values with the existence of Cumba. Thus, this study presents important findings about the importance of plan typology in the effectiveness of wind-driven ventilation strategies in modern dwellings.     

Influence of molding conditions on the shrinkage and roundness of injection molded parts

During the plastic injection molding process, one of the biggest challenges is shrinkage which deteriorates the quality of produced parts. To control and reduce this defect, the essential way is to perfectly determine the variables like molding parameters. In this study, the effects of molding parameters including packing pressure, melt temperature, and cooling time on shrinkage and roundness have been investigated experimentally. Also, the relationship among initial molding parameters, the cavity pressure, and mold temperature was investigated. The results of this experimental study and analysis fulfill various requirements of plastic injection molding and clarify the relationship between molding conditions and the overall quality of produced parts. This study illustrated that packing pressure and melt temperature are dominant factors which determine the quality of parts.     

Design of internal MRI coils using ultimate intrinsic SNR

Object  Internal MRI coils have important applications in diagnostic and interventional studies. Since they can be placed very close to the region of interest in the body, they are favored over external coils in applications where high-resolution images are required. In this paper it is demonstrated that ultimate intrinsic SNR (UISNR) and the optimum coil sensitivity solutions can be used to make new coil designs with higher intrinsic SNR. Materials and methods  In this study, UISNR, which is the maximum attainable value of the intrinsic SNR, is used as a measure of performance and as a design criterion. As an example, a novel endorectal MRI coil is designed. The design is tested with phantom and patient studies. Results  An endorectal coil is built to demonstrate the effectiveness of the design strategy. ISNR of the endorectal coil approximates the UISNR to 72%. Conclusion  An internal coil design method that takes advantage of the UISNR and optimum coil sensitivity calculations was presented. This method can also be used to design better internal MRI coils for different applications.     

Providing predictions on distributed HMMs with privacy

As forecasting is increasingly becoming important, hidden Markov models (HMMs) are widely used for prediction in many applications such as finance, marketing, bioinformatics, speech recognition, and so on. After creating an HMM, the model owner can start providing predictions. When the model is owned by one party, predictions can be easily provided. However, it becomes a challenge when the model is horizontally or vertically distributed between various parties, even competing companies. The parties want to integrate the split models they own for better forecasting purposes. Due to privacy, financial, and legal reasons; however, they do not want to share their models. We investigate how such parties produce predictions on the distributed model without violating their privacy. We then analyze our proposed schemes in terms of accuracy, privacy, and performance; and finally present our findings.     

Evolution of beta-amyloid induced neuropathology: magnetic resonance imaging and anatomical comparisons in the rodent hippocampus

Alzheimer’s disease (AD) is characterized by the anatomical appearance of β-amyloid (βA) plaques and neurofibrillary tangles. These changes are also associated with cyclical inflammation, oxidative damage and, as inferred from the autopsied brains of patients, progressive injury to neurons. Here, we report the short-term effects of an intrahippocampal injection of the toxic βA peptide fragment 25–35 in rats using quantitative magnetic resonance imaging (MRI) methods. Physiological changes within the cornu ammonis 1 (CA1) region of the hippocampus were monitored using a 1.5 T scanner at time points of 0.25, 1 and 24 h, and 7 and 14 days post injection. Spin echo T2-weighted (T2W) and diffusion weighted (DW) images were sequentially acquired. Apparent diffusion coefficients (ADC) were calculated and compared with histological alterations. A significant elevation in mean ADC values (17%) was observed in the ipsilateral CA1 at 14 days. The ADC changes were associated with disrupted pyramidal cells and nuclear lysis observed in histological sections. The contralateral CA1 exhibited a significant decrease in mean ADC of 15% at 14 days post treatment. Histological changes in the contralateral hippocampus suggested decreased neuronal density. T2W maps revealed no significant differences between the active βA 25–35 fragment and its non-active analog, βA 35–25. In conclusion, these results, based on changes in hippocampal ADC, demonstrate that the βA 25–35 treatment induced pathology consistent with edema and cellular necrosis. This is the first report describing the evolution of AD-like pathology in an animal model using DW imaging.     

Optical solitons through an anharmonic vibrational mode

An optic field interacting with an infrared active vibrational mode with a cubic nonlinearity is considered. The slowly varying envelope of the electric field is shown to satisfy the nonlinear Schrödinger equation. Various aspects of the model are discussed.     

The aroma of grapes. Localisation and evolution of free and bound fractions of some grape aroma components c.v. Muscat during first development and maturation

The localisation of some aroma components in the different parts of the berry of Muscat grape varieties was studied. The evolution of these compounds was also monitored during the development and maturation of the fruit. The aromatic substances were certain terpenols in free and glycosidically bound forms and certain aromatic alcohols, benzyl and 2-phenyl ethyl alcohols. The skin was the richest in free and bound terpenols in the berry. The ratio of bound free terpenols in skin, pulp and juice was similar. Free terpenols (in particular geraniol and nerol) were much more abundant in skin than in juice. It was possible to distinguish between the two Muscat varieties studied here using their levels of bound terpenols. These were abundant from the green stage of the grape berry onwards; their levels increased during development of the fruit to reach very high levels at the end of maturation. The bound terpenols have a considerable aroma potential, mainly located in grape skins, which it would be interesting to make use of in new wine technology.     

Does PTCA in acute myocardial infarction affect mortality and reinfarction rates? A quantitative overview (meta-analysis) of the randomized clinical trials

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) is often performed after acute myocardial infarction (AMI) either as an adjuvant to thrombolytic therapy or instead of thrombolysis. The effect of PTCA in AMI on mortality and reinfarction has remained unclear, with the available randomized trials indicating inconsistent results. METHODS AND RESULTS: A systematic overview (meta-analysis) of the randomized trials was conducted to assess the effect of PTCA in AMI on mortality and reinfarction rates. Data from 7 trials in which primary PTCA was evaluated and 16 trials in which PTCA after thrombolysis was studied were included in this overview, comprising a total of 8496 patient. The trials represented different approaches to the timing of PTCA after AMI. The trials of PTCA after thrombolytic therapy were also categorized according to the different protocols with respect to the routine or elective character of PTCA in the invasive group. A reduction in short-term (6 week) mortality (odds ratio, 0.56; 95% CI, 0.33, 0.94) and in the combined outcome of short-term mortality and nonfatal reinfarction (odds ratio, 0.53; 95% CI, 0.35, 0.80) was observed in the trials comparing primary PTCA with thrombolytic therapy. In contrast, in trials in which an approach of thrombolysis and PTCA was compared with thrombolytic therapy alone, there was no important difference in early mortality, with an apparent reduction in mortality between 6 and 52 weeks. The lower mortality between 6 and 52 weeks among 6-week survivors seemed to be restricted to the subgroup of trials in which PTCA was used as a routine strategy (odds ratio, 0.58; 95% CI, 0.39, 0.87). CONCLUSIONS: Although the analyses of the various categories of trials suggest that primary PTCA may be more beneficial than thrombolytic therapy in AMI, these data should be interpreted cautiously unless confirmed by larger studies. In contrast, the addition of various other strategies of PTCA to thrombolytic therapy does not convincingly indicate a clinically different outcome than if a more conservative strategy is followed, in which PTCA is used only if clinically indicated. Some specific strategies, however, such as rescue PTCA in high-risk patients with occluded arteries, may be of benefit.