Appendix
Now, we have to prove that the Hessian Matrix of \(JTC_{NvbAS} (Q,k,L,A,S,m)\) at point \((Q^{*},k^{*},A^{*},S^{*})\) for fixed m and \(L\in \left[ {L_i ,L_{i-1} } \right] \) is positive definite.
We first obtain the Hessian Matrix H as follows:
$$\begin{aligned} H=\left[ {{\begin{array}{cccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right] \end{aligned}$$
where
$$\begin{aligned} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}= & {} \frac{2D}{Q^{3}}\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right)>0\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}= & {} \frac{D\pi \sigma \sqrt{L}\varphi (k)}{Q}>0\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}= & {} \frac{\alpha a}{A^{2}}>0\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}= & {} \frac{\alpha b}{S^{2}}>0\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial k}= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}\\= & {} -\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial A}= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}=-\frac{D}{Q^{2}}\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial S}= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}=-\frac{D}{Q^{2}m}\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}=0\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}=0\\ \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}=0\\ \left| {H_{11} } \right|= & {} \left| {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}} \right|>0 \nonumber \\= & {} \frac{2D}{Q^{3}}\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) >0 \end{aligned}$$
Therefore, \(\left| {H_{11} } \right| >0\)
$$\begin{aligned} \left| {H_{22} } \right|= & {} \left| {{\begin{array}{cc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial k}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}} \\ \end{array} }} \right| \\= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}\\&-\;\left( {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}} \right) ^{2}\\= & {} \frac{2D}{Q^{3}}\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left( {\frac{D\pi \sigma \sqrt{L}\varphi (k)}{Q}} \right) \\&-\;\left( {-\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) ^{2}\\= & {} \left( {A+\frac{S}{m}{+}\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left( {\frac{2D^{2}\pi \sigma \sqrt{L}\varphi (k)}{Q^{4}}} \right) {-}\frac{\left( {D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) } \right) ^{2}}{Q^{4}}\\= & {} \frac{\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L} \psi (k)+c(L)} \right) \left( {2D^{2}\pi \sigma \sqrt{L}\varphi (k)} \right) -\left( {D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) } \right) ^{2}}{Q^{4}}\\= & {} \frac{2D^{2}}{Q^{4}}\pi \sigma \sqrt{L}\phi (k) \left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \\&-\;\frac{D^{2}}{Q^{4}}\left( {\pi \sigma \sqrt{L}} \right) ^{2}\left( {2\varphi (k)\psi (k)- \left( {\phi (k)-1} \right) ^{2}} \right)>0\\= & {} \frac{2D^{2}}{Q^{4}}\pi \sigma \sqrt{L}\varphi \left( k \right) \left( {A+\frac{S}{m}+C\left( L \right) } \right) +\frac{D^{2}}{Q^{4}}\left( {\pi \sigma \sqrt{L}} \right) ^{2}\left( {\phi \left( k \right) -1} \right) ^{2}>0 \end{aligned}$$
Because, \(\phi (k)>0,\psi (k)>0\) and \(\left( {\phi (k)-1} \right) ^{2}>0\) for all \(k>0\) [28].
Therefore, \(\left| {H_{22} } \right| >0\).
$$\begin{aligned} \left| {H_{33} } \right|= & {} \left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial A}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}} \\ \end{array} }} \right| \\= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}\\&\times \,\left( {\begin{array}{c} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}} \\ -\left( {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}} \right) ^{2} \\ \end{array}} \right) \\&-\;\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial k}\\&\times \,\left( {\begin{array}{c} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}} \\ -\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A} \\ \end{array}} \right) \\&+\;\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial A}\\&\times \,\left( {\begin{array}{c} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k} \\ -\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}} \\ \end{array}} \right) \\= & {} \frac{2D}{Q^{3}}\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left[ {\left( {\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) -0} \right] \\&+\left( {\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) \left( {-\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}\left( {\frac{\alpha a}{A^{2}}} \right) +\frac{D}{Q^{2}}.0} \right) \\&-\;\frac{D}{Q^{2}}\left( {-\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}.0+\frac{D}{Q^{2}}\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \\= & {} \frac{2D}{Q^{3}}\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left[ {\left( {\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) } \right] \\&-\;\left( {\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) \left( {\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}\left( {\frac{\alpha a}{A^{2}}} \right) } \right) \\&+\;\frac{D}{Q^{2}}\left( {\frac{D}{Q^{2}}\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \\ \end{aligned}$$
If
$$\begin{aligned}&\frac{2D}{Q^{3}}\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left[ {\left( {\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) } \right] \\&\qquad +\;\frac{D}{Q^{2}}\left( {\frac{D}{Q^{2}}\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \\&\quad >\left( {\frac{D\pi \sigma \sqrt{L} \left( {\phi (k)-1} \right) }{Q^{2}}} \right) \left( {\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}\left( {\frac{\alpha a}{A^{2}}} \right) } \right) \end{aligned}$$
Then,
$$\begin{aligned}&=\frac{2D}{Q^{3}}\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left[ {\left( {\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) } \right] \\&\quad -\;\left( {\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}}\right) \left( {\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}\left( {\frac{\alpha a}{A^{2}}} \right) } \right) +\frac{D}{Q^{2}}\left( {\frac{D}{Q^{2}}\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \\&>0 \end{aligned}$$
Therefore, \(\left| {H_{33}}\right| >0\).
$$\begin{aligned} \left| {H_{44} } \right|= & {} \left| {{\begin{array}{cccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial S}} \\ \times \,{\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ \times \,{\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right| \\ \end{aligned}$$
$$\begin{aligned}= & {} \frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}\\&\times \,\left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right| \\&-\;\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial k}\\&\times \,\left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right| \\&+\;\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial A}\\&\times \,\left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right| \\&-\;\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial S}\\&\times \,\left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}} \\ \end{array} }} \right| \end{aligned}$$
Now,
$$\begin{aligned}&\left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right| \\&\quad =\left( {\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \left( {\left( {\frac{\alpha a}{A^{2}}} \right) \left( {\frac{\alpha b}{S^{2}}-0} \right) } \right) -0.\left( {0.\frac{\alpha b}{S^{2}}-0.0} \right) +0.\left( {0.0-\frac{\alpha a}{A^{2}}.0} \right) \\&\quad =\left( {\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&\qquad \times \; \left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right| \\&\quad =\left( {-\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) \left( {\left( {\frac{\alpha a}{A^{2}}.\frac{\alpha b}{S^{2}}-0} \right) } \right) -0.\left( {\left( {-\frac{D}{Q^{2}}} \right) .\frac{\alpha b}{S^{2}}-\frac{D}{Q^{2}m}.0} \right) \\&\qquad +\;0.\left( {\left( {-\frac{D}{Q^{2}}} \right) .0-\frac{\alpha a}{A^{2}}.\left( {-\frac{D}{Q^{2}m}} \right) } \right) \\&\quad =-\left( {\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&\qquad \times \; \left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right| \\&\quad =\left( {\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) \left( {\left( {0.\frac{\alpha b}{S^{2}}-0} \right) } \right) \\&\qquad -\;\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}.\left( {\left( {-\frac{D}{Q^{2}}} \right) .\frac{\alpha b}{S^{2}}-\frac{D}{Q^{2}m}.0} \right) +0.\left( {\left( {-\frac{D}{Q^{2}}} \right) .0-0.\left( {-\frac{D}{Q^{2}m}} \right) } \right) \\&\quad =-\left( {\frac{D^{2}\pi \sigma \sqrt{L}\phi (k)}{Q^{3}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&\qquad \times \; \left| {{\begin{array}{ccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}} \\ \end{array} }} \right| \\&\quad =\left( {-\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) \left( {0.0-\frac{\alpha a}{A^{2}}.0} \right) \\&\qquad -\;\frac{D\pi \sigma \sqrt{L}\phi (k)}{Q}.\left( {\left( {-\frac{D}{Q^{2}}} \right) .0\left( {-\frac{D}{Q^{2}m}} \right) .\frac{\alpha a}{A^{2}}} \right) -\frac{D}{Q^{2}}.\left( {0.0-0.\left( {-\frac{D}{Q^{2}m}} \right) } \right) \\&\quad =-\left( {\frac{D^{2}\pi \sigma \sqrt{L}\phi (k)}{Q^{3}m}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \\ \end{aligned}$$
$$\begin{aligned} \left| {H_{44} } \right|= & {} \left| {{\begin{array}{cccc} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial Q\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial k\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A^{2}}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial A\partial S}} \\ {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial Q}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial k}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S\partial A}}&{} {\frac{\partial ^{2}JTC_{NvbAS} (Q,k,L,A,S,m)}{\partial S^{2}}} \\ \end{array} }} \right| \\ \end{aligned}$$
$$\begin{aligned}= & {} \left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left( {\frac{2D^{2}\pi \sigma \sqrt{L}\phi (k)}{Q^{4}}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&-\;\left( {-\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) \left( {-\frac{D\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}\left( {\frac{\alpha a}{A^{2}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) } \right) \\&+\;\left( {-\frac{D}{Q^{2}}} \right) \left( {\frac{D^{2}\pi \sigma \sqrt{L}\phi (k)}{Q^{3}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) -\left( {-\frac{D}{Q^{2}m}} \right) \left( {\frac{D^{2}\pi \sigma \sqrt{L}\phi (k)}{Q^{3}m}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \\= & {} \left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left( {\frac{2D^{2}\pi \sigma \sqrt{L}\phi (k)}{Q^{4}}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&-\;\left( {\frac{D^{2}\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) ^{2}\left( {\frac{\alpha ^{2}ab}{A^{2}S^{2}}} \right) -\left( {\frac{D^{3}\pi \sigma \sqrt{L}\phi (k)}{Q^{5}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&-\;\left( {\frac{D^{3}\pi \sigma \sqrt{L}\phi (k)}{Q^{5}m^{2}}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \end{aligned}$$
If
$$\begin{aligned}&\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left( {\frac{2D^{2}\pi \sigma \sqrt{L}\phi (k)}{Q^{4}}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&\quad >\left( {\frac{D^{2}\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) ^{2}\left( {\frac{\alpha ^{2}ab}{A^{2}S^{2}}} \right) +\left( {\frac{D^{3}\pi \sigma \sqrt{L}\phi (k)}{Q^{5}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&\qquad +\;\left( {\frac{D^{3}\pi \sigma \sqrt{L}\phi (k)}{Q^{5}m^{2}}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) , \end{aligned}$$
then
$$\begin{aligned}&\left( {A+\frac{S}{m}+\pi \sigma \sqrt{L}\psi (k)+C(L)} \right) \left( {\frac{2D^{2}\pi \sigma \sqrt{L}\phi (k)}{Q^{4}}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&\quad -\;\left( {\frac{D^{2}\pi \sigma \sqrt{L}\left( {\phi (k)-1} \right) }{Q^{2}}} \right) ^{2}\left( {\frac{\alpha ^{2}ab}{A^{2}S^{2}}} \right) -\left( {\frac{D^{3}\pi \sigma \sqrt{L}\phi (k)}{Q^{5}}} \right) \left( {\frac{\alpha b}{S^{2}}} \right) \\&\quad -\;\left( {\frac{D^{3}\pi \sigma \sqrt{L}\phi (k)}{Q^{5}m^{2}}} \right) \left( {\frac{\alpha a}{A^{2}}} \right) >0 \end{aligned}$$
Therefore, \(\left| {H_{44}}\right| >0\).