Rooftop photovoltaic (PV) systems for industrial halls: Achieving economic benefit via lowering energy demand

Industrial halls are characterized with their relatively high roof-to-floor ratio, which facilitates ready deployment of renewable energy generation, such as photovoltaic (PV) systems, on the rooftop. To promote deployment of renewable energy generation, feed-in tariff (FIT) higher than the electricity rate is available in many countries to subsidize the capital investment. FIT comes in different forms. For net FIT, in order to maximize the economic benefit, surplus electricity generation at each hour is desirable.One way to achieve surplus electricity generation is by increasing generation capacity, which is synonymous to higher capital investment. In fact, surplus electricity generation can also be achieved by lowering the energy demand of the building. This particularly the case for industrial halls, which are usually subject to high energy demand for space conditioning in order to remove the excess heat gain due to the many power-intensive processes.Building energy performance simulation tools can be used to explore the different building design options that could lower the energy demand. In this paper, single-objective optimization on investment return will be deployed to study the cost effectiveness among different options in lowering energy demand. It will be demonstrated with a case study of a warehouse.     

Cadmium levels of kidney from 10 different pig genetic lines in Vojvodina (northern Serbia)

Concentration of cadmium was investigated in the kidney of 480 pigs from 10 different genetic lines, produced in Vojvodina (northern Serbia). This element was determined by flame atomic absorption spectrometry after mineralisation by dry ashing. The genetic line of pigs had no influence on the cadmium levels of kidney (P > 0.05). The cadmium levels ranged from 0.168 to 1.160 mg/kg, with an average of 0.368 mg/kg. Only 1.9% of kidney slightly exceeded the maximum level set by EU and Serbian legislation.     

Physical‐chemical characteristics and oxidative stability of oil obtained from lyophilized raspberry seed

Fresh raspberry (Rubus idaeus), cultivar Willamette, was freeze‐dried (lyophilization). A byproduct of lyophilization is “fine dust” of raspberry consisting of finely ground raspberry fruit body and seed. The seeds were separated. The seed oil was isolated and its physical and chemical characteristics were determined. Parameters that characterize the seed and quality of the oil were examined, including fatty acid composition, oxidative stability under different storage conditions, and radical‐scavenging activity. The fatty acid composition was determined by GC/FID and the contents of the dominant fatty acids were found as: oleic 16.92%, linoleic 54.95%, and α‐linolenic acid 23.97%. The oxidative stability of the oil was poor. The induction period by Rancimat test at 100 °C was 5.2 h. The radical‐scavenging activity is similar to that of resveratrol [1,3‐benzenediol 5‐(1^E‐2‐4‐hydroxy‐phenyl‐ethyl)]. Although this product is used in the candy industry, it would be far more useful if raspberry oil of satisfactory quality could be extracted. This paper demonstrates that sifted lyophilized seeds can be used for the extraction of oils. This process allows for maximal usage of the byproducts, reduces losses and it increases the development of new products.     

Flavonoids as Potent Scavengers of Hydroxyl Radicals

Oxidative stress is a fundamental principle in the pathophysiology of many diseases. It occurs when the production of reactive oxygen species exceeds the capacity of the cell defense system. The hydroxyl radical is a reactive oxygen species that is commonly formed in vivo and can cause serious damage to biomolecules, such as lipids, proteins, and nucleic acids. It plays a role in inflammation‐related diseases, like chronic inflammation, neurodegeneration, and cancer. To overcome excessive oxidative stress and thus to prevent or stop the progression of diseases connected to it, scientists try to combat oxidative stress and to find antioxidant molecules, including those that scavenge hydroxyl radical or diminish its production in inflamed tissues. This article reviews various methods of hydroxyl radical production and scavenging. Further, flavonoids, as natural plant antioxidants and essential component of the human diet, are reviewed as compounds interacting with the production of hydroxyl radicals. The relationship between hydroxyl radical scavenging and the structure of the flavonoids is discussed. The structural elements of the flavonoid molecule most important for hydroxyl radical scavenging are hydroxylation of ring B and a C2–C3 double bond connected with a C‐3 hydroxyl group and a C‐4 carbonyl group. Hydroxylation of ring A also enhances the activity, as does the presence of gallate and galactouronate moieties as substituents on the flavonoid skeleton.     

Effect of synthesis parameters on structural and mechanical properties of Ti3Al–Nb–Mo intermetallic compound obtained by powder metallurgy techniques

The influence of microstructure, heat treatment and alloying addition on mechanical and fracture properties of Ti₃Al-based intermetallic at room and elevated temperatures was studied. Ti₃Al–11Nb–1Mo (mole fraction, %) alloy was consolidated via powder metallurgy processing by mechanical alloying (MA) and hot pressing (HP). MA powders were characterized using XRD and SEM-EDS. Optimum MA duration was 25 h and HP conditions of 1350 °C, 2 h, 35 MPa. After HP, solution treatment at 1050 °C for 1 h and water quenching α₂+β Widmanstätten microstructure is present, while subsequent aging at 800 °C during 24 h induces small content of O-phase. High fraction of β-phase is a direct consequence of Mo. Compression tests were performed from room temperature to 750 °C in vacuum. The yield strength of compacts increases with temperature up to 250 °C (pyramidal slip systems activation), after which it decreases. Ductility increases throughout the whole temperature range. The presence of O phase contributed to ductility increase in aged alloys, while negligibly lowering yield strength. Registered drop in the yield strength of aged alloys compared with non-aged ones was mostly influenced by precipitation of α″₂ particles. Mixed fracture modes are operative at all temperatures.     

Fiber-shaped Co modified with Au and Pt crystallites for enhanced hydrogen generation from sodium borohydride

This work presents the study of catalytic activity of the fiber-shaped Co decorated with low amounts of Au or Pt nanoparticles for the hydrolysis of sodium borohydride in alkaline conditions. The morphology, structure and composition of the prepared catalysts were examined using Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Analysis and Inductively Coupled Plasma Optical Emission Spectroscopy.It was found that the decoration of the fiber-shaped Co with the Au or Pt nanoparticles allows enhancing of catalytic activity for the hydrolysis of sodium borohydride, compared with that of the pure fiber-shaped Co.     

The laboratory investigation of the clothing microclimatic layers in accordance with the volume quantification and qualification

Some of the researches expressed connection between the numbers and size of the microclimatic air layers on thermal insulation of clothing. The insulation of the ensembles is much affected by the air enclosed between the clothing layers. In loose fitting clothing, they are less subjected to compression and thus add more to the overall thermal insulation. The heat and the moisture are released from the body into the microclimatic layers, subsequently changing properties of the entrapped air. The volume of the microclimatic air layers was investigated by the use of non-contact 3D CAD method. The temperature and humidity changes of microclimatic layers were also observed. This paper represents layer by layer quantification of the clothing ensemble volume with jackets as covering garment and the impact of the microclimatic volume on the clothing insulation. The three-level laboratory testing was performed with human subjects dressed in selected ensembles.