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Background Jute fiber is one of the most versatile natural fibers that is widely used as a raw material for packaging, textiles, and construction; and as a reinforcement in composite materials for heavy-duty applications. In the past, acid hydrolysis and mechanical treatment via the ball milling method were common in the extraction of cellulose nanofiber (CNFs) from natural plant fibers. However, there are some drawbacks of using those methods where there will be a huge quantity of acidic wastewater generated when the acid hydrolysis method is performed. Method This study investigated the potential use of a combination of chemical and mechanical methods in the extraction of jute CNFs. Through this method, the jute fibers were first chemically treated using sodium hydroxide (NaOH), sodium chlorite (NaClO 2) and sulphuric acid (H 2SO 4) to remove the non-cellulosic elements followed by mechanical milling by using a planetary ball mill. Results The shape and size of the obtained CNFs were observed under a field emission scanning electron microscope (FESEM). This study revealed that jute CNFs were successfully extracted through the combination of chemical and mechanical treatment methods where the obtained CNFs reveal themselves in smooth fibrous morphology with a diameter of 23 nm and 150-200nm in length. Conclusions Jute cellulose nanofibers were successfully drawn out from raw jute fibers by means of a combination of chemical and mechanical treatment. The results obtained confirmed that the chemomechanical method is an effective technique for isolating the CNFs and its potential use as reinforcement material was explained.

Summary: Numerous cooling techniques are available to reduce photovoltaic module (PV) temperature and thus improve PV efficiency. Sometimes, the manufacturing cost of some PV cooling techniques is higher as compared with their power productivity, and thus the cost parameter is needed to be taken into consideration to justify producing certain PV cooling techniques. This paper is intended to link the manufacturing cost of the PV cooler with its output power by providing an economic analysis as there is a research gap in previous studies related to the economic aspect of these products. It proposes a new method by defining and deriving a new parameter called the PV cooling technique production cost effectiveness factor whose value is affected by the PV efficiency gained of a PV with and without a cooler, the manufacturing cost of the PV cooling technique, and the cost of one watt of PV power. Based on the value of this new factor, three possible classifications are suggested. They are production/not production cost effective or neutral. To determine the optimum PV cooler, the minimum value of the PV cooling technique production cost effectiveness factor is defined. The applicability conditions and limitations of the proposed method are illustrated. It is shown that the PV cooling technique production cost effectiveness factor and its minimum value are helpful in classifying the PV cooling techniques based on their power productivity and manufacturing cost. This parameter may have a potential to be used by PV cooling technique designers and manufacturers on making their design decisions. [ABSTRACT FROM AUTHOR]