Economical assessment of different HVAC systems for an operating room: Case study for different Turkish climate regions

In this study, the annual energy consumptions of four different heating, ventilation and air conditioning (HVAC) systems serving to operation rooms (ORs) located at five different cities (Izmir, Antalya, Istanbul, Ankara and, Erzurum) in Turkey are analyzed. The study is performed for four different HVAC systems: (a) 100% fresh air system (System I), (b) 100% fresh air with half air volume rate at night period (System II), (c) 100% fresh air with half air volume rate at night period and heat recovery unit (System III), (d) 50% fresh air with half air volume rate at night period and with heat recovery and mixing units (System IV). Life cycle cost (LCC) for 20 years life span is calculated for the considered systems. It is found that System IV considerably reduces energy consumption and it is economically proper for the considered cities. The rate of energy consumption and LCC reductions are greater for the cities with extreme climate condition having relatively low specific humidity ratio. Using System IV instead of System I reduces OR energy consumption by 74% for the city of Erzurum which has a cold and dry climate.     

Computational intelligence techniques for HVAC systems: A review

Buildings are responsible for 40% of global energy use and contribute towards 30% of the total CO2 emissions. The drive to reduce energy use and associated greenhouse gas emissions from buildings has acted as a catalyst in the development of advanced computational methods for energy efficient design, management and control of buildings and systems. Heating, ventilation and air-conditioning (HVAC) systems are the major source of energy consumption in buildings and ideal candidates for substantial reductions in energy demand. Significant advances have been made in the past decades on the application of computational intelligence (CI) techniques for HVAC design, control, management, optimization, and fault detection and diagnosis. This article presents a comprehensive and critical review on the theory and applications of CI techniques for prediction, optimization, control and diagnosis of HVAC systems. The analysis of trends reveals that the minimisation of energy consumption was the key optimization objective in the reviewed research, closely followed by the optimization of thermal comfort, indoor air quality and occupant preferences. Hardcoded Matlab program was the most widely used simulation tool, followed by TRNSYS, EnergyPlus, DOE-2, HVACSim+ and ESP-r. Metaheuristic algorithms were the preferred CI method for solving HVAC related problems and in particular genetic algorithms were applied in most of the studies. Despite the low number of studies focussing on multi-agent systems (MAS), as compared to the other CI techniques, interest in the technique is increasing due to their ability of dividing and conquering an HVAC optimization problem with enhanced overall performance. The paper also identifies prospective future advancements and research directions.     

盐胁迫环境下腐植酸类物质对小麦生长及矿物营养吸收的影响

对在不同浓度的盐胁迫条件下,叶面喷施液态腐植酸和土壤施用腐植酸类物质对小麦作物生长和矿物营养吸收的影响进行了研究。通过添加不同量的NaCl得到不同的盐浓度环境。腐植酸类物质在作物种植前一个月施用,液态腐植酸在种苗发芽后20d和35d喷施于小麦叶面。腐植酸类物质的施用量为0、1g/kg、2g/kg,液态腐植酸的浓度为0、0.1%、0.2%。盐度对小麦生长具有负面影响,它会降低小麦对除Na、Mn以外的矿物营养的吸收,影响小麦干重。通过在土壤施用腐植酸类物质可以增加小麦对N的吸收,叶面施用腐植酸可增加其对P、K、Mg、Na、Cu和Zn的吸收。研究结果显示：在土壤中施用腐植酸类物质,不同盐浓度与施用量之间存在较好的相关性,但叶面喷施时盐度和喷施量之间相关性并不明显。在盐胁迫环境的影响下,叶面喷施腐植酸的初始浓度和土壤中施用的腐植酸类物质的初施量都增加了作物对营养元素的吸收。     

Synthesis of poly(epichlorohydrin‐g‐methyl methacrylate) and poly(epichlorohydrin‐g‐styrene) graft copolymers by a combination of cationic and photopolymerization methods

Poly(epichlorohydrin‐g‐styrene) and poly (epichlorohydrin‐g‐methyl methacrylate) graft copolymers were synthesized by a combination of cationic and photoinitiated free‐radical polymerization. For this purpose, first, epichlorohydrin was polymerized with tetrafluoroboric acid (HBF₄) via a cationic ring‐opening mechanism, and, then, polyepichlorohydrin (PECH) was reacted ethyl‐hydroxymethyl dithio sodium carbamate to obtain a macrophotoinitiator. PECH, possessing photolabile thiuram disulfide groups, was used in the photoinduced polymerization of styrene or methyl methacrylate to yield the graft copolymers. The graft copolymers were characterized by ¹H‐NMR spectroscopy, differential scanning calorimetry, and gel permeation chromatography. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Single and multiple property CD control of sheet forming processes via reduced order infinite horizon MPC algorithm

In this article, a reduced order infinite horizon model predictive control (MPC) algorithm for sheet forming processes is explained, and its closed loop performance is studied by using a paper production process as a typical sheet forming process. The proposed algorithm has a very light computational burden due to a significant decrease in the number of variables which is achieved by applying Karhunen–Loeve transformation (KLT) to the sheet profile and finding the lower order subspace which extracts the significant features of the disturbance. Then, the optimal control action in the lower order subspace is found by solving the infinite horizon MPC formulation, and the corresponding solution of the optimization problem is projected back to the original space to be implemented on the real plant. Also, a novel approach is introduced for the solution of multiple property control problem in sheet forming processes, where two or more sheet profiles with different process dynamics are to be controlled by using a single set of actuators. It is explained that the dimensional mismatch problem for the reduced order controller can be solved by using an intermediate subspace, and simulations show that the proposed algorithm performs successfully for paper production processes.     

The Assessment of Irrigation Efficiency in Buyuk Menderes Basin

While extending irrigated areas to augment agricultural production, irrigation efficiency should be increased not only to improve the agricultural production but also to obtain the sustainable use of valuable and limited water resources. Through the use of Data Envelopment Analysis (DEA), which is a linear programming technique to determine the relative efficiency of a decision-making unit, it is possible to decide whether the use of water in an irrigation district is efficient or not. In this study, an input oriented DEA model is constituted to focus on the efficient use of inputs, and the method is applied to the irrigation districts having similar types of agriculture in the Buyuk Menderes Basin, Turkey. This paper aims to determine the efficient irrigation district(s), in other words where the application of water is the most profitable, considering two inputs; water volume supplied and the total irrigated area, and one output, the total value of agricultural production. The weight restrictions consistent with decision makers’ value judgements are added as constraints into the DEA models to prevent excessive weight flexibility assigned to inputs and outputs. The results have provided the efficiency scores of the irrigation districts and numerically delineated desired features of the irrigation districts for maximum efficiency. The analyses for three study years have inferred the robustness of the results. It is concluded that DEA is a practical tool for detecting local inefficiencies and proposing possible improvements for irrigation districts that could offer the greatest potential for growth.     

Coronary artery bypass grafting versus percutaneous coronary intervention in end-stage kidney disease: A systematic review and meta-analysis of clinical studies

The most significant complication of end-stage kidney disease (ESKD) is cardiovascular disease, mainly coronary artery disease (CAD). Although the effective treatment of CAD is an important prognostic factor, whether percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) is better for treating CAD in this group of patients is still controversial. We searched Pubmed/Medline, Web of Science, Embase, the Cochrane Central Register of Controlled Trials articles that compared the outcomes of CABG versus PCI in patients with ESKD requiring dialysis. A total of 10 observational studies with 39,666 patients were included. Our analysis showed that when compared to PCI, CABG had lower risk of need for repeat revascularization (relative risk [RR] = 2.25, 95% confidence interval [CI] 2.1–2.42, p < 0.00001) and cardiovascular death (RR = 1.19, 95% CI 1.14–1.23, p < 0.00001) and higher risk for short-term mortality (RR = 0.43, 95% CI 0.38–0.48, p < 0.00001). There was no statistically significant difference between the PCI and CABG groups in the risk for late mortality (RR = 1.05, 95% CI 0.97–1.14, p = 0.25), myocardial infarction (RR = 1.05, 95% CI 0.46–2.36, p = 0.91) or stroke (RR = 1.02, 95% CI 0.64–1.61, p = 0.95). This meta-analysis showed that in ESKD patients requiring dialysis, CABG was superior to PCI in regard to cardiovascular death and need for repeat revascularization and inferior to PCI in regard to short term mortality. However, this meta-analysis has limitations and needs confirmation with large randomized controlled trials.     

Nanoscale communication with molecular arrays in nanonetworks

Molecular communication is a promising nanoscale communication paradigm that enables nanomachines to exchange information by using molecules as communication carrier. Up to now, the molecular communication channel between a transmitter nanomachine (TN) and a receiver nanomachine (RN) has been modeled as either concentration channel or timing channel. However, these channel models necessitate exact time synchronization of the nanomachines and provide a relatively low communication bandwidth. In this paper, the Molecular ARray-based COmmunication (MARCO) scheme is proposed, in which the transmission order of different molecules is used to convey molecular information without any need for time synchronization. The MARCO channel model is first theoretically derived, and the intersymbol interference and error probabilities are obtained. Based on the error probability, achievable communication rates are analytically obtained. Numerical results and performance comparisons reveal that MARCO provides significantly higher communication rate, i.e., on the scale of 100 Kbps, than the previously proposed molecular communication models without any need for synchronization. More specifically, MARCO can provide more than 250 Kbps of molecular communication rate if intersymbol time and internode distance are set to 2 μs and 2 nm, respectively.