Hot press as a sustainable direct recycling technique of aluminium: mechanical properties and surface integrity

Meltless recycling technique has been utilized to overcome the lack of primary resources, focusing on reducing the usage of energy and materials. Hot press was proposed as a novel direct recycling technique which results in astoundingly low energy usage in contrast with conventional recycling. The aim of this study is to prove the technical feasibility of this approach by characterizing the recycled samples. For this purpose, AA6061 aluminium chips were recycled by utilizing hot press process under various operating temperature (Ts = 430, 480, and 530 °C) and holding times (ts = 60, 90, and 120 min). The maximum mechanical properties of recycled chip are Ultimate tensile strength (UTS) = 266.78 MPa, Elongation to failure (ETF) = 16.129%, while, for surface integrity of the chips, the calculated microhardness is 81.744 HV, exhibited at Ts = 530 °C and ts = 120 min. It is comparable to theoretical AA6061 T4-temper where maximum UTS and microhardness is increased up to 9.27% and 20.48%, respectively. As the desired mechanical properties of forgings can only be obtained by means of a final heat treatment, T5-temper, aging after forging process was employed. Heat treated recycled billet AA6061 (T5-temper) are considered comparable with as-received AA6061 T6, where the value of microhardness (98.649 HV) at 175 °C and 120 min of aging condition was revealed to be greater than 3.18%. Although it is quite early to put a base mainly on the observations in experimental settings, the potential for significant improvement offered by the direct recycling methods for production aluminium scrap can be clearly demonstrated. This overtures perspectives for industrial development of solid state recycling processes as environmentally benign alternatives of current melting based practices

Life Cycle Assessment on the Direct Recycling Aluminium Alloy AA6061 Chips and Metal Matrix Composite (MMC-AlR)

Metallic material processing plays a significant role in terms of global environmental impact which contributes to the climate change phenomena that is a serious international environmental concern and the subject of much research and debate. Thus, energy- and resource-efficient strategies in the metal shaping technology domain need to be identified urgently. A frequent theme in the debates that surround waste and resources management is the extent to which the recycling of metallic materials offers genuine benefits to the environment. Solid state recycling techniques allow the manufacture of high density aluminium alloy parts directly from production scrap. In this paper the environmental impacts associated with ‘meltless’ scrap processing routes through hot press forging process with varying parameter has been studied. A comparative analysis has been performed with two different type of materials which is recycling aluminium alloy (AA6061) chips and metal matrix composite (AA6061 chips + 2% alumina) in order to quantify and compare the environmental benefits for both materials. The LCA data are collected using Simapro 8.0.4   software.   The   additional   materials   used   in   a   product   resulted   higher environmental impact. Metal matrix composite had higher value of midpoint and endpoint impact categories compare to aluminium alloy chips

Chemical Constituents of Hedyotis dichotoma and their Biological Activity

Two compounds, isovitexin and ursolic acid, were isolated from the aerial parts of Hedyotis dichotoma. Anti-microbial assays indicated that isovitexin was active against fungus and candida. The structures of both compounds were assigned using modern spectroscopic techniques

Cardamonin inhibits COX and iNOS expression via inhibition of p65NF-κB nuclear translocation and Iκ-B phosphorylation in RAW 264.7 macrophage cells

Cardamonin, a chalcone isolated from the fruits of a local plant Alpinia rafflesiana, has demonstrated anti-inflammatory activity in cellular models of inflammation. In this report, we evaluated the ability of cardamonin to suppress both NO and PGE2 synthesis, iNOS and COX-2 expression and enzymatic activity, and key molecules in the NF-κB pathway in order to determine its molecular target. Cardamonin suppressed the production of NO and PGE2 in interferon-γ (IFN-γ)- and lipopolysaccharide (LPS)-induced RAW 264.7 cells. This inhibition was demonstrated to be caused by a dose-dependent down-regulation of both inducible enzymes, iNOS and COX-2, without direct effect upon iNOS or COX-2 enzyme activity. Subsequently we determined that the inhibition of inducible enzyme expression was due to a dose-dependent inhibition of phosphorylation and degradation of I-κBα, which resulted in a reduction of p65NF-κB nuclear translocation. We conclude that cardamonin is a potential anti-inflammatory drug lead that targets the NF-κB pathway

Chemical Constituents of Vitex ovata (Verbenaceae)

Three compounds, luteolin, ursolic acid and meta-hydroxybenzoic acid were isolated from the leaves of Vitex ovata. The structures of the compounds were identified using modern spectroscopic techniques

The Alkaloids of Ophiorrhiza communis and O. tomentosa

Two alkaloids, harman and strictosidinic acid, were isolated from the leaves and bark of Dphiorrhiza communis Linn. Strictosidinic acid was also isolated from Dphiorrhiza tomentosa Jack. These structural assignments were based on their physical and spectroscopic data

Effect of compounds isolated from natural products on IFN-γ/LPS- induced nitric oxide production in RAW 264.7 macrophages

The current study was designed to evaluate whether compounds isolated from local medicinal plants in Malaysia suppressed nitric oxide (NO) production in inflammation. The murine monocytic macrophage (RAW 264.7) cell line was used as a target cell and activated by interferon-γ. (IFN-γ.) and lipopolysaccharide (LPS). Our current study has identified four phytochemicals, namely atrovirinone, cardamonin, flavokawin B, and zerumbone, that inhibit pathological NO generation. These compounds are candidates for further bioassay studies to determine their suitability as drug leads

Chemopreventive effects of a curcumin‐like diarylpentanoid [2,6‐bis(2,5‐dimethoxybenzylidene)cyclohexanone] in cellular targets of rheumatoid arthritis in vitro

Aim: Synovial fibroblast has emerged as a potential cellular target in progressive joint destruction in rheumatoid arthritis development. In this study, BDMC 33 (2,6‐bis[2,5‐dimethoxybenzylidene]cyclohexanone), a curcumin analogue with enhanced anti‐inflammatory activity has been synthesized and the potency of BDMC 33 on molecular and cellular basis of synovial fibroblasts (SF ) were evaluated in vitro. Methods: Synovial fibroblast cells (HIG ‐82) were cultured in vitro and induced by phorbol‐12‐myristate acetate (PMA) to stimulate the expression of matrix metalloproteinase (MMP s) and pro‐inflammatory cytokines. The protective effects of BDMC 33 were evaluated toward MMP activities, pro‐inflammatory cytokine expression and nuclear factor kappa‐B (NF ‐κB) activation by using various bioassay methods, including zymography, Western blotting, reverse transcription polymerase chain reaction, immunofluorescense microscopy and electrophoretic mobility shift assay. Results: The results showed that BDMC 33 significantly inhibited the pro‐gelatinase B (pro‐MMP ‐9) and collagenase activities via suppression of MMP ‐1 in activated SF. In addition, BDMC 33 strongly suppressed MMP‐3 gene expression as well as inhibited COX‐2 and IL‐6 pro‐inflammatory gene expression. We also demonstrated that BDMC 33 abolished the p65 NF‐κB nuclear translocation and NF‐κB DNA binding activity in PMA ‐stimulated SF. Conclusions: BDMC33 represents an effective chemopreventive agent and could be used as a promising lead compound for further development of rheumatoid arthritis therapeutic intervention

LC-DAD-ESI-MS analysis of nitric oxide inhibitory fractions of tenggek burung (Melicope ptelefolia Champ. ex Benth)

Solvent–solvent fractionation of the methanolic extract of the popular Malay traditional vegetable “tenggek burung” (Melicope ptelefolia), followed by nitric oxide inhibition assay on RAW 264.7 cells revealed that the most active components reside mainly in hexane and dichloromethane fractions. Online profiling of the nitric oxide (NO) inhibitive fractions of the tenggek burung using liquid chromatography coupled diode array detection and electrospray ion-trap tandem mass spectroscopy (LC–DAD–ESI-MSn), has identified seven constituents. The compounds were identified as kokusaginine (1), compound 2, [kokusagine, (2a) or 5-methoxymaculine (2b)], 2,4,6-trihydroxy-3-prenylacetophenone (3), 2,4,6-trihydroxy-3-geranylacetophenone (4), 2,4,6-trihydroxy-3-geranylgeranylacetophenone (5), 3-[4-O-(3,7-dimethyl-2,6-octadienyl)phenyl]-2-propenoic acid (6) and 2,4,6-trihydroxy-3-farnesylgeranylacetophenone (7). The identity of compounds 1, 4 and 6 were unequivocally confirmed by isolation and spectroscopic evidences, other constituents are tentatively identified, based on their UV, MS, MSn and comparison with literature data. Kokusaginine (1) demonstrated in vitro activity on NO inhibition in murine peritoneal macrophages